Answer Explanations

SAT Practice Test #9
Section 1: Reading Test
QUESTION 1

Choice D is the best answer. Throughout the passage, the narrator
describes a visit to her family’s ink shop. The narrator’s father and uncles
are employed at the shop, and in the third and fifth paragraphs thenarrator describes her father’s interactions with a customer. Her father
praises the color, sound, and smell of an ink sample as indicators of the
ink’s quality. This interaction leads the narrator to conclude in the lastparagraph, “I was very proud to hear Father speak of our family’s ink thisway.” Therefore, the passage is best summarized as a character’s visit toher family’s ink shop that deepens her appreciation of her family’s work.
Choice A is incorrect. Although the narrator’s arrival at her family’s
ink shop does spark memories of her Precious Auntie, these memories
center on Precious Auntie’s beliefs about creativity, including theconviction that inferior ink produces inferior thought. The narrator’s
thoughts on Precious Auntie occur in the fourth paragraph, so choice A
isn’t the best summary of the overall passage. Choice B is incorrect.
Although the passage describes the narrator’s surprise visit to theink shop and a reunion with her uncles, these events occur in the firstparagraph. Therefore, choice B doesn’t provide the best summary of
the passage as a whole. Choice C is incorrect because the narrator
doesn’t make any reference to her father’s ambitions.

QUESTION 2

Choice B is the best answer. In the fourth paragraph, the narrator
recounts her Precious Auntie’s belief that “you can never be an artist
if your work comes without effort.” Her Precious Auntie states thatwhen the physical act of writing is done with an “inkstick along an
inkstone,” this process requires an artist to “take the first step tocleansing your mind and your heart. You push and you ask yourself,
What are my intentions? What is in my heart that matches my mind?”
In the following paragraphs, the narrator recalls the pride she felt
while listening to her father describe the high quality of the ink thather family had worked hard to produce. Therefore, a main theme of thepassage is that quality is achieved through deliberate effort.
501PART 4 | Eight Official Practice Tests with Answer Explanations

Choice A is incorrect. Although family relationships form a backdrop
to the passage, the nurturing of these relationships isn’t a main theme.
Choice C is incorrect. Although the passage does emphasize that hard
work produces higher quality writing than that which is produced
through minimal work, the passage doesn’t mention that hard work
results in material compensation. Choice D is incorrect. Although
the passage discusses the role of concentrated effort in creative
expression, a main theme of the passage isn’t that creativity needs tobe expressed concretely.

QUESTION 3

Choice B is the best answer. In the first sentence of the second
paragraph, the narrator states: “I tried to notice everything so I could
later tell GaoLing what I had seen.” She then proceeds to describe thefloors of the family’s ink shop, the walls and display cases, and thevarious items for sale. According to the third paragraph, these include aninkstick “with a top shaped like a fairy boat,” another inkstick with “abird shape,” and a collection of ink cakes “embellished with designs ofpeonies and bamboo.” Therefore, throughout the passage, the narrator is
portrayed as someone who is attuned to her immediate surroundings.
Choice A is incorrect. Although the narrator describes herself as shy,
the people she interacts with aren’t unfamiliar to her because they are
members of her family whom she has met before. Choices C and D areincorrect because the narrator isn’t portrayed as sympathetic to the needsof others (choice C) or anxious about her responsibilities (choice D).

QUESTION 4

Choice A is the best answer. Big Uncle and Little Uncle offer Old
Widow Lau and the narrator a seat at a table reserved for customers
upon their arrival at the narrator’s family’s ink shop. According to thetenth sentence of the first paragraph, “Old Widow Lau refused theirinvitation three times, exclaiming that my father and uncles must be
too busy for visitors.” Old Widow Lau’s rejection of the uncles’ offer
is characterized as insincere, as the next sentence of that paragraphshows that she doesn’t actually want to leave the shop: “She madeweak efforts to leave.” Instead, her gestures are intended to inspire
exaggerated insistence from the uncles, such that it isn’t until theuncles’ “fourth insistence, [that Old Widow Lau and the narrator]
finally sat.” Therefore, it can be most reasonably inferred from thepassage that Old Widow Lau’s reluctance to stay for tea is feigned
because she isn’t genuinely firm in her resolve.
Choice B is incorrect because the passage doesn’t imply that Old
Widow Lau’s reluctance is inconsiderate or that the family has beenplanning her visit. Choice C is incorrect because the shop isn’t
unusually busy. Instead, only one customer is mentioned in thepassage. Choice D is incorrect because the passage doesn’t state or
imply that Old Widow Lau is exhausted from her journey.
502

Answer Explanations | SAT Practice Test #9

QUESTION 5

Choice C is the best answer. The previous question asks what canbe most reasonably inferred from the passage about Old Widow Lau’s
reluctance to stay for tea. The answer, that her reluctance is feigned
because she isn’t genuinely firm in her resolve, is best supported by
the tenth and eleventh sentences of the first paragraph: “Old Widow
Lau refused their invitation three times, exclaiming that my father anduncles must be too busy for visitors. She made weak efforts to leave.”
Choices A, B, and D are incorrect because the cited lines don’t
support the answer to the previous question. Instead, they describe
the narrator and Old Widow Lau’s arrival at the shop (choice A), theirinitial reception by the uncles (choice B), and the hospitality the uncles
lavish on them once they are seated (choice D).

QUESTION 6

Choice A is the best answer. In the second paragraph, the narrator
describes the “shiny” glass display cases at her family’s ink shop andhow the silk-wrapped boxes of ink inside these cases “looked so muchnicer [in the shop] than they had in the ink-making studio at Immortal
Heart village.” Therefore, the narrator indicates that the contrast
between the ink-making studio at Immortal Heart village and her family’s
ink shop is that the ink shop displays the family’s ink more impressively.
Choices B, C, and D are incorrect because the narrator doesn’t stateor imply that her family’s ink shop, in comparison to the ink-making
studio at Immortal Heart village, is more conveniently located for the
public (choice B), provides greater individual attention to customers(choice C), or offers a larger space for presenting products (choice D).

QUESTION 7

Choice C is the best answer. In the fourth paragraph, the narrator
summarizes Precious Auntie’s artistic philosophy: when you write
without effort, “you do not have to think. You simply write what is
swimming on the top of your brain. And the top is nothing but pond
scum, dead leaves, and mosquito spawn.” In other words, anything
written too quickly, and therefore without concerted effort andthought, would be synonymous with the debris floating on top of apool of water. Therefore, it is reasonable to infer that Precious Auntie
would consider a hastily written first draft of a story to be essentiallyworthless in and of itself.
Choice A is incorrect because Precious Auntie’s description ofwork made without effort is exclusively negative; therefore, it isn’t
reasonable to infer that she would praise a hastily written story draft asemotionally raw and powerful. Choice B is incorrect because Precious
Auntie’s artistic philosophy is concerned solely with the quality of theartist’s output rather than with the satisfaction the artist experiences.
Choice D is incorrect because whether a hastily produced work would
be inappropriately analytical isn’t discussed in the passage.
503

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 8

Choice C is the best answer. The previous question asks what can bereasonably inferred about Precious Auntie’s view of a hastily written
first draft of a story, based on the artistic philosophy expressed in the
fourth paragraph. The answer, that she would consider such a story
to be essentially worthless in and of itself, is best supported by thesixth and seventh sentences of the fourth paragraph, which describe
Precious Auntie’s view of writing produced without effort: “You simply
write what is swimming on the top of your brain. And the top is
nothing but pond scum, dead leaves, and mosquito spawn.”
Choices A, B, and D are incorrect because the cited lines don’t support
the answer to the previous question. Instead, they transition between
the scene in the ink shop and the narrator’s memories of Precious
Auntie (choice A), summarize Precious Auntie’s assessment of ink
quality (choice B), and describe the process of creating good writing
through concerted effort (choice D).

QUESTION 9

Choice B is the best answer. In the last sentences of the
fourth paragraph, the narrator describes Precious Auntie’s artistic
philosophy, or, more specifically, the questions that an artist is forced to
ask when working with concerted effort: “You push and you ask yourself,
What are my intentions? What is in my heart that matches my mind?”
With the second question, Precious Auntie highlights how an artist muststrive to create work that resembles, or corresponds with, what is in boththe artist’s heart and mind. Therefore, the word “matches,” as used inthis sentence, most nearly means corresponds with.
Choices A, C, and D are incorrect because in the context of thepassage, “matches” means corresponds with, not competes against(choice A), runs counter to (choice C), or treats equally (choice D).

QUESTION 10

Choice C is the best answer. In the fifth paragraph, the narrator’s
father demonstrates the quality of an inkstick to a customer. He strikes
the inkstick, and the narrator describes “a sound as clean and pure
as a small silver bell.” Therefore, the word “clean,” as used in thisparagraph to describe a sound that the inkstick produced, most nearlymeans distinct, or clear.
Choices A, B, and D are incorrect because in the context of thepassage, “clean” means distinct, not complete (choice A), skillful(choice B), or upright (choice D).

QUESTION 11

Choice D is the best answer. The first paragraph of the passage
introduces research by Harvard psychology professor Daniel
Wegner demonstrating that the Internet is changing “the way our504

Answer Explanations | SAT Practice Test #9

memories function.” One finding of Wegner’s study, as stated in
the second paragraph, is that “when people have access to searchengines, they remember fewer facts and less information because theyknow they can rely on ‘search’ as a readily available shortcut.” In thethird paragraph, Wegner claims that his study shows how “the Internet
has become part of a transactive memory source, a method by which[humans’] brains compartmentalize information,” such that “computers
and technology as well are becoming virtual extensions of [human]
memory.” The remainder of the passage details Wegner’s experiments
and findings. Thus, the main purpose of the passage is to sharethe findings of a study examining the effect of computer use on
memory recall.
Choice A is incorrect. Although the author suggests in thesixth paragraph that technology may interfere with critical thinking,this isn’t the focus of Wegner’s experiments, nor is illustrating thisposition the main purpose of the passage. Choices B and C areincorrect because the passage doesn’t support the assertion thatpeople have become overly dependent on computers for storing
information (choice B) or that humans’ capacity for memory is much
weaker that it once was (choice C).

QUESTION 12

Choice D is the best answer. The fifth paragraph details the results ofthe fourth experiment of Wegner’s study, where participants were more
likely to recall digital folder locations where statements they typed
were saved than the actual statements themselves. The first sentenceof the last paragraph summarizes why this result may not be alarming:“And even though we may not be taxing our memories to recall distinct
facts, we are still using them to consider where the facts are locatedand how to access them.” In this sentence, the author paraphrases
Wegner’s view that although human memory is changing as a resultof technology, this doesn’t indicate that human memory is declining,as people are relying on their memory to access specific types of
information. Therefore, this sentence best supports the idea that
reliance on computers doesn’t necessarily diminish human memory.
Choices A, B, and C are incorrect because the cited lines don’t support
the idea that reliance on computers doesn’t necessarily diminish
human memory. Instead, they introduce the topic of Wegner’s research(choice A), provide examples of the types of information that people
may now rely on the Internet to provide (choice B), and concede that
the Internet may diminish critical thinking skills (choice C).

QUESTION 13

Choice D is the best answer. In the third paragraph, the author
outlines Wegner’s theory of a “transactive memory source.” According
to Wegner, transactive memory is a “network of memory,” where an
individual can access information that he or she can’t personally505

PART 4 | Eight Official Practice Tests with Answer Explanations

recall from a particular source. The author illustrates this idea in thesecond sentence of this paragraph, with the example of “a husband[who] relies on his wife to remember a relative’s birthday.” Thus,
the reference to remembering a relative’s birthday mainly serves
to illustrate the concept of a transactive memory source using afamiliar situation.
Choice A is incorrect. Although the situation of a husband relying on
his wife’s memory does suggest that closely related people tend tohave shared memories, this isn’t the main purpose of this reference inthe context of the passage. Choice B is incorrect because the example
doesn’t demonstrate how people initially developed external sourcesof memory. Choice C is incorrect because the function of the example
isn’t to emphasize the effectiveness and accuracy of transactive
memory sources. Instead, its function is to make the abstract conceptof transactive memory more easily understandable.

QUESTION 14

Choice B is the best answer. In the third paragraph, Wegner describes
transactive memory as a “network of memory where you don’t haveto remember everything in the world yourself.” Instead, the burdenof storing information is shifted to transactive memory sourcesthat can function as “extensions of [human] memory.” Examples ofsources provided in the fourth paragraph of the passage include cell
phones, GPS devices, and search engines. What these examples havein common is that they store information, such as phone numbers,
directions, and general knowledge, so that a person doesn’t haveto commit this information to memory. A written list of a user’s
passwords for different websites serves the same function as theseexamples. Although remembering a list of passwords for different
websites is conceivable without a list, keeping such a list shifts
the burden of storing readily memorable information away from theuser because the list preserves the information in place of the user’s
memory. Therefore, based on the passage, a written list of a user’s
passwords for different websites would be considered a transactive
memory source.
Choices A, C, and D are incorrect because they don’t accurately
exemplify transactive memory sources. A souvenir brought home froma memorable trip (choice A) may evoke memories of that place for theowner. However, it doesn’t preserve actual information in the way theexamples provided in the passage do. A library database that helps
users locate specific books (choice C) may seem similar to a searchengine. However, it doesn’t store information that would otherwise
be readily memorable in the way that a search engine can help a user
remember an actor’s name or a detail of geography, according to thefourth paragraph of the passage. Instead, it helps a library patronnavigate a system that is typically far too vast to be committed tomemory. A website that helps users plan and make travel arrangements

506

Answer Explanations | SAT Practice Test #9(choice D) may help facilitate transactions in the form of ticket
purchases or hotel reservations. However, it doesn’t store informationthat the user would otherwise memorize.

QUESTION 15

Choice B is the best answer. In the last sentence of thethird paragraph, the author states that “computers and technology. . . are becoming virtual extensions of our memory.” In other words,
computers and technology are becoming memory sources that serveas additions to human memory. Thus, “extensions of,” as used in thepassage, most nearly means additions to.
Choices A, C, and D are incorrect because in the context of thepassage, “extensions of” means additions to, not delays in (choice A),
lengths of (choice C), or developments of (choice D).

QUESTION 16

Choice C is the best answer. The fifth paragraph of the passage
describes four experiments that Wegner conducted to demonstrate
his theory of a transactional memory source. The first experiment,
described in the second sentence of this paragraph, found thatparticipants “were more likely to think of computer terms like ‘Yahoo’or ‘Google’ after being asked a set of difficult trivia questions.” Thesecond, third, and fourth experiments explored participants’ tendency
to remember the location of information rather than the information
itself. Therefore, the discussion of the experiments, most specificallythe first experiment, suggests that people are inclined to think ofspecific information sources in response to being asked to provide
facts that aren’t already familiar to them.
Choice A is incorrect. Although some of the subjects in the second
experiment did memorize information that later became inaccessible,
this act of memorization didn’t cause the subjects to think of specificinformation sources. Choice B is incorrect. Although participants inthe fourth experiment were told their work would be saved in specificfolders, they weren’t directed to develop a system for organizing andsaving content. Choice D is incorrect because none of the experiments
involved participants being prompted to identify terms related todependence on computers.

QUESTION 17

Choice A is the best answer. The previous question asks, based on
Wegner’s experiments, when people would be inclined to think ofspecific information sources. The answer, that being asked to provide
facts that aren’t already familiar to them provokes this response, isbest supported by the second sentence of the fifth paragraph: “In thefirst experiment, participants demonstrated that they were more likely
to think of computer terms like ‘Yahoo’ or ‘Google’ after being asked a
set of difficult trivia questions.”
507

PART 4 | Eight Official Practice Tests with Answer Explanations

Choices B, C, and D are incorrect because the cited lines don’t
support the answer to the previous question. Instead, they describe
the different parameters for the participants in the second andthird experiments (choice B), summarize the results of the second
and third experiments (choice C), and summarize the results of the
fourth experiment (choice D).

QUESTION 18

Choice A is the best answer. The second sentence of thesixth paragraph states: “Students who have trouble remembering
distinct facts, for example, may struggle to employ those facts incritical thinking.” In other words, students who find it difficult toremember information may find it challenging to utilize that information
to develop logical arguments. Therefore, the word “employ,” as used in
the context of this sentence, most nearly means utilize.
Choices B, C, and D are incorrect because in the context of thepassage, “employ” means utilize, not enroll (choice B), exert (choice C),
or assign (choice D).

QUESTION 19

Choice C is the best answer. The passage explains that in the
fourth experiment participants were given statements and folder
locations where they were told those statements would be saved.
On the graph, the bar farthest to the left represents those who
remembered both elements of the information given to them during theexperiment. This bar rises to a point midway between 15% and 20%.
Therefore, according to the graph, approximately 17% of participants
remembered both parts of the information given to them during thefourth experiment.
Choice A is incorrect because none of the groups represented on thegraph comprised 7% of participants. Choices B and D are incorrect
because neither 10% (choice B) nor 30% (choice D) of participants
remembered both elements of the information given to them during
the fourth experiment. Instead, 10% remembered statements but not
folder locations (according to the second bar from the left), while 30%
remembered folder locations but not statements (according to thethird bar from the left).

QUESTION 20

Choice D is the best answer. The largest single group of participants
represented on the graph is composed of those who rememberednothing, as indicated by the bar that is farthest to the right. Why
approximately 40% of participants could not remember the statementsor the folder locations isn’t explained by the description of the
fourth experiment in the fifth paragraph of the passage. Therefore, the508Answer Explanations | SAT Practice Test #9

most likely explanation for the findings regarding the largest single
group of participants represented on the graph is that there isn’t enoughinformation to determine the cause of the results for those participants.
Choices A, B, and C are incorrect because these speculations aren’t
supported by the passage. There isn’t enough information provided
about the fourth experiment to know whether the participants who
could remember nothing focused on remembering the folder locations(choice A), attempted to remember the statements and the folder
locations (choice B), or didn’t attempt to remember any specific pieces
of information (choice C).

QUESTION 21

Choice A is the best answer. Throughout the passage, the author
describes experiments conducted on guppies to determine the guppies’
rate of and types of evolutionary change. The first paragraph outlines
the reason why these fish were an optimal choice for this research:
their “unstinting rate of reproduction makes guppies ideally suited forstudying the rate of evolution.” Therefore, the first paragraph mainly
serves to establish the reason why a certain species was selected forscientific observation.
Choice B is incorrect because the purpose of the first paragraphisn’t to illustrate the value of studying the offspring of a particularanimal shortly after birth. Instead, guppies were selected because of
their rapid rate of reproduction and weren’t only studied shortly after
being born, according to the passage. Choices C and D are incorrect.
Although the fourth paragraph does introduce a new method ofscientific inquiry (experimental evolution), the first paragraph doesn’t
mainly serve to introduce a theory at the center of an ongoing scientificdebate (choice C) or offer a rationale for the prevalence of a new field of
scientific inquiry (choice D).

QUESTION 22

Choice B is the best answer. The third sentence of thesecond paragraph states, “A lucky guppy is born above a waterfall ora set of rapids, which keep out the predatory fish called pike cichlids
found in calmer downstream waters.” In other words, pike cichlids
normally eat guppies, but waterfalls and rapids can create naturalbarriers that prevent these predators from entering certain areas where
guppies live. Thus, in describing the living conditions of guppies,
the author indicates that a “lucky guppy” is one that inhabits anenvironment that provides natural protection from predators.
Choices A and C are incorrect because the author doesn’t indicate thatbeing born in a major river with an established guppy population isan advantage for a guppy (choice A) or that there are risks associatedwith living near a waterfall or that guppies benefit by avoiding suchrisks (choice C). Choice D is incorrect because the author doesn’t
indicate that there is an advantage for guppies living in calmer
509

PART 4 | Eight Official Practice Tests with Answer Explanations

downstream waters. Instead, the author notes that calmer downstream
waters are where guppies’ predators live, making these zones moredangerous for guppies than the areas above waterfalls or rapids.

QUESTION 23

Choice D is the best answer. In the last paragraph, the author
describes an experiment in which Reznick’s team removed groups ofguppies from areas with large populations of pike cichlid predators andrelocated them into areas above waterfalls and rapids. According to thesecond sentence of this paragraph, “Although small predatory killifish
occurred in these new sites, these fish do not pose anything close to
the danger of the cichlids.” This sentence provides the best evidence
for the conclusion that the streams used by Reznick’s team were notentirely free of predators, as they contained populations of killifish.
Choices A, B, and C are incorrect because the cited lines don’t provide
the best evidence for the conclusion that the streams used by Reznick’s
team were not entirely free of predators. Instead, they explain theadvantage for guppies living above waterfalls or rapids (choice A),
outline the correlation between numbers of pike cichlids and guppy
mortality rates (choice B), and explain the growing popularity of“experimental evolution” among scientists (choice C).

QUESTION 24

Choice A is the best answer. According to the fourth paragraph, theexistence of streams in Trinidad with populations of guppies and those
without guppies led Reznick to the conclusion that he could conduct
experiments by altering the guppy populations in various streams.
According to the second sentence of the fourth paragraph, Reznick
realized he could “‘treat streams like giant test tubes by introducing
guppies or predators’ to places they had not originally occurred,
and then watch as natural selection acted on the guppies.” Reznick
uses the phrase “giant test tubes” in this sentence to suggest thatcertain streams can provide suitable experimental conditions for his
guppy research.
Choices B, C, and D are incorrect because the phrase “giant test tubes”
serves to characterize certain streams as suitable for experimental
research, not to suggest that those streams promote cooperative
behaviors among guppies used as subjects in experimental studies(choice B), increase the rate of genetic change among guppies(choice C), or assist scientists in solving environmental problems in
the natural habitat of guppies (choice D).

QUESTION 25

Choice C is the best answer. The fourth paragraph describes Reznick’s
rationale for moving populations of guppies from one body of water
to another. The last sentence of the paragraph states, “This kind ofreal-world manipulation of nature is called ‘experimental evolution,’
510

Answer Explanations | SAT Practice Test #9

and it is growing increasingly popular among scientists working withorganisms that reproduce quickly enough for humans to be able to see
the outcome within our lifetimes.” In other words, the fact that thistype of research is “growing increasingly popular” means that it is
becoming more widespread. Thus, the word “popular” as used in thepassage most nearly means widespread.
Choices A, B, and D are incorrect because in the context of thepassage, “popular” means widespread, not accessible (choice A),
suitable (choice B), or likable (choice D).

QUESTION 26

Choice B is the best answer. Reznick’s team found that guppies, when
moved from predator-ridden environments to a site where there was
not the same level of predation, “evolved to mature later, and havefewer, bigger offspring in each litter, just like the guppies that naturally
occurred in the cichlid-free streams,” according to the fourth sentenceof the last paragraph. If it were discovered that the new site into which
Reznick released the guppies were inhabited by fish found to be as
predatory as the cichlids in the original sites, this discovery would
undermine Reznick’s findings. Such a finding would mean that thepressure of predation on the guppies remained constant from one site
to the next. As a consequence, some other factor or factors would
be responsible for the developmental changes in the guppies that
Reznick’s team recorded.
Choice A is incorrect. If guppies examined in other parts of the globe
were found to exhibit genetic shifts in traits at a different rate fromthe guppies Reznick examined, these findings would not undermine
his research because they would have occurred outside the confinesof his experimental conditions. Choice C is incorrect. If experimental
evolution were shown to be harmful to the environment, this finding,though important, would not undermine Reznick’s findings. Choice D
is incorrect. If the descendants of Reznick’s transplanted fish wereproven to mature later than the guppies living below the waterfall, thisfinding would support, rather than undermine, Reznick’s findings.

QUESTION 27

Choice A is the best answer. The last sentence of the passage states,“Other studies of guppies in Trinidad have shown evolutionary change
in as few as two and a half years, or a little over four generations, withmore time required for genetic shifts in traits such as the ability to form
schools and less time for changes in the colorful spots and stripes ona male’s body.” That is, certain traits, such as physical markings, seemto change more quickly than other traits, such as aspects of group
behavior. Thus, it can most reasonably be inferred from the passage
that the experiments in Trinidad have shown that some genetic traits
will evolve more readily than others.

511

PART 4 | Eight Official Practice Tests with Answer Explanations

Choices B, C, and D are incorrect because the experiments in Trinidad
led to conclusions about guppies’ rate of evolutionary changes. Theseexperiments did not lead to an identification of other dangerous
predators (choice B), an analysis of how certain guppies thrive betterin predator-ridden environments (choice C), or an examination as tohow evolutionary changes can be prevented in a natural environment(choice D).

QUESTION 28

Choice D is the best answer. The previous question asks what canmost reasonably be inferred about guppies based on the experimentsin Trinidad described in the passage. The answer, that some guppy
genetic traits will evolve more readily than others, is best supported by
the last sentence of the passage: “Other studies of guppies in Trinidad
have shown evolutionary change in as few as two and a half years, ora little over four generations, with more time required for genetic shifts
in traits such as the ability to form schools and less time for changes
in the colorful spots and stripes on a male’s body.”
Choices A, B, and C are incorrect because the cited lines don’t support
the answer to the previous question. Instead, they pose a question
central to Reznick’s research (choice A), describe the conditions thatled Reznick to consider conducting experimental evolution tests in
Trinidad (choice B), and describe how Reznick’s team removed guppies
from one area and reintroduced them in another (choice C).

QUESTION 29

Choice D is the best answer. The number of offspring produced
by guppies living in the south slope high-predation environment isindicated by the first bar from the left in figure 1. This bar rises to apoint midway between 6 and 7 on the graph. Therefore, according tofigure 1, guppies living in the south slope high-predation environment
produced a mean number of offspring between 6 and 7.
Choice A is incorrect because 2 to 3 offspring were produced by
guppies living in the south slope low-predation environment, rather
than those living in the high-predation environment, as indicated by
the second bar from the left in figure 1. Choice B is incorrect because 3
to 4 offspring were produced by guppies living in the north slope lowpredation environment, rather than guppies living in the south slope
high-predation environment, as indicated by the bar that is farthest to
the right in figure 1. Choice C is incorrect because none of the groups
represented in figure 1 produced 5 to 6 offspring.

QUESTION 30

Choice C is the best answer. The graph shows that the mean
embryo mass in a low-predation environment for south slope guppies(second bar from the left) is higher than mean embryo mass in a

512

Answer Explanations | SAT Practice Test #9

high-predation environment for south slope guppies (bar farthest to theleft). A similar relationship exists for north slope guppies, as the mean
embryo mass in a low-predation environment (bar farthest to the right)
is higher than the mean embryo mass in a high-predation environment(third bar from the left). Meanwhile, a comparison of south slope highpredation environments (bar farthest to the left) to north slope highpredation environments shows no difference in mean embryo mass.
The graph shows that while there is a slightly lower mean embryo
mass in north slope low-predation environments (bar farthest to theright) than in south slope low-predation environments (second bar fromthe left), this difference is only 0.2 mg, which is considerably less thanthe difference that results from comparing the low- and high-predation
environments in each of the two locations. Therefore, the conclusion
about the mean mass of guppy embryos that is best supported by
figure 2 is that the predation level observed in each environment had
more of an effect on mean embryo mass than did slope location.
Choice A is incorrect because slope location wasn’t a better indicatorof mean embryo mass than was the predation level observed in eachenvironment. Instead, the mean masses of embryos in the two locations
were roughly equivalent. Choice B is incorrect because the mean
embryo mass of guppies born in the north slope environments didn’t
exceed the mean embryo mass of guppies born in the south slope
environments. Guppies living in high-predation environments in both
north and south slope locations had embryos with the same mass,
while those living on the north slope in low-predation environments
had embryos with a slightly lower mass than that of south slope
guppies in low-predation environments. Therefore, the mean embryo
mass of guppies born in the south slope environment exceeded themean embryo mass of guppies born in the north slope environment.
Choice D is incorrect because guppies born in low-predation
environments didn’t have a mean embryo mass less than that ofguppies born in high-predation environments. Instead, these guppies
had a greater mass.

QUESTION 31

Choice B is the best answer. Figure 1 shows that guppies from lowpredation environments (represented on the graph by second andfourth bars from the left) had smaller litters, or fewer guppy offspring,
than did guppies from high-predation environments (represented by the
first and third bars from the left). Similarly, figure 2 shows that guppies
from low-predation environments (the second and fourth bars from theleft) also had embryos with a greater mean mass than did guppies fromhigh-predation environments (the first and third bars from the left).
Choice A is incorrect. Although figure 1 does support the conclusionthat guppies from low-predation environments have fewer offspringthan those from high-predation environments, neither figure indicates
the time required for guppies to reach full maturity. Choice C isincorrect because neither figure indicates the survival rate of guppies,
513

PART 4 | Eight Official Practice Tests with Answer Explanations

and figure 2 directly contradicts the conclusion that guppies from lowpredation environments have less mean embryo mass than those fromhigh-predation environments. Choice D is incorrect. Although figure 2
supports the conclusion that guppies from low-predation environments
have a greater mean embryo mass than those from high-predation
environments, figure 1 directly contradicts the conclusion that
guppies from low-predation environments produce a greater number ofoffspring than those from high-predation environments.

QUESTION 32

Choice D is the best answer. In the passage, Sara T. Smith addresses
the Second Anti-Slavery Convention of American Women. In thesecond sentence of the first paragraph, Smith states that confronting
slavery is “a question of justice” and that it involves “considerationsof immense importance to the welfare and prosperity of our country.”
In the third paragraph, Smith argues that women shouldn’t be deterredfrom participating in the abolitionist cause. In the last paragraph, sheargues that women “cannot remain inactive” in confronting slavery
as “our country is as dear to us as to the proudest statesman. . . . Let
our course, then, still be onward!” Therefore, Smith’s main purpose in
the passage is to encourage women to see their participation in theabolitionist cause as just and important.
Choices A and C are incorrect because Smith doesn’t accuse fellow
abolitionists of overlooking the contributions that women have madeto the movement (choice A) or make the case that women’s rights aremeaningless while slavery exists (choice C). Choice B is incorrect.
Although Smith quotes the Declaration of Independence in thethird paragraph, the main purpose of the passage isn’t to argue that thecauses of abolition and women’s rights are continuations of the spiritof the American Revolution.

QUESTION 33

Choice A is the best answer. Throughout the passage, Smith poses
questions that aren’t answered explicitly until the last paragraph, but
the leading tone of the speech makes it clear that the implied answer
to these questions is “no.” In the second paragraph, Smith questions
her critics’ claim that upholding humanitarian values undermines
conventional feminine virtues. In the third paragraph, she wonders
how women can “have no interest” in the subject of slavery when it
could lead to the destruction of their families through war. In the lastparagraph, she asks women numerous questions and then answers
them with a “no.” Thus, a technique that Smith uses throughout thepassage to advance her main point is to present her claims in the formof rhetorical questions that mostly have implicit negative answers.
Choice B is incorrect. Although Smith questions the assertions that
her opponents made, she doesn’t criticize her opponents themselves
by quoting self-contradictory remarks they have made. Choice C
514

Answer Explanations | SAT Practice Test #9

is incorrect. Although Smith makes use of vivid language and imagery
throughout the passage, she doesn’t illustrate each of her central
ideas with an emotionally powerful anecdote. Choice D is incorrect.
Although it is implied that Smith considers her views to be reasonable,
she doesn’t present them as universally held.

QUESTION 34

Choice B is the best answer. In the first sentence of the passage,
Smith introduces the argument that slavery is a “political question”
and therefore not “within the ‘province of woman.’” In the second
sentence, Smith voices her opposition to this argument: “It is not truethat [slavery] is merely a political question, it is likewise a questionof justice, of humanity, of morality, of religion.” In other words,
slavery is too broad a problem to be classified solely as “political,”in Smith’s view. However, in the fourth paragraph, Smith returns
to the political aspect of the argument at hand by addressing how
women must engage in the subject of slavery on a political scale. She
argues that “admitting [slavery] to be a political question” doesn’tmean that women have “no interest in the welfare of our country,” aswomen must criticize slavery and its “unjust laws” and seek to stop
the nation’s “downward course” by choosing to not “remain inactive.”
Therefore, Smith develops her argument about slavery as a “politicalquestion” over the course of the passage by dismissing the designation
as too narrow but then demonstrates its relevance to her audience.
Choice A is incorrect. Although Smith does offer alternative ways ofdefining the problem of slavery, she doesn’t claim that the designationof slavery as a “political question” is outdated, but rather that it isinsufficient. Choice C is incorrect because Smith doesn’t contend thatthe designation of slavery as a “political question” has become trite,
nor does she invite her audience to revitalize it. Choice D is incorrect.
Although Smith’s argument is intertwined with questions of genderroles, she doesn’t describe the meaning the designation of a “politicalquestion” has for men and then challenge women to embrace it.

QUESTION 35

Choice B is the best answer. In the first sentence of the passage,
Smith relays a claim: “We are told that it is not within the ‘provinceof woman,’ to discuss the subject of slavery; that it is a ‘politicalquestion,’ and we are ‘stepping out of our sphere,’ when we take partin its discussion.” In the next sentence, Smith rejects this claim: “It is
not true that it is merely a political question, it is likewise a questionof justice, of humanity, of morality, of religion.” She then argues thatthe subject of slavery “involves considerations of immense importanceto the welfare and prosperity of our country, enters deeply into thehome-concerns, the every-day feelings of millions of our fellow
beings” and expands upon this point by providing an example of thedifference, under slavery, between laborers who are enslaved and those515

PART 4 | Eight Official Practice Tests with Answer Explanations

who are within the “dignity of conscious manhood.” Therefore, thebest summary of the first paragraph is that Smith rejects a claim andelaborates on her reasons for doing so.
Choice A is incorrect. Although Smith may outline a conventional
viewpoint in the first paragraph, she doesn’t present evidence
to support it. Choice C is incorrect. Although Smith introduces
her subject in the first paragraph, she doesn’t provide historicalbackground for understanding it. Choice D is incorrect. Although
Smith does identify a problem in the first paragraph, she doesn’t
propose steps to remedy it.

QUESTION 36

Choice A is the best answer. In the first sentence of the second
paragraph, Smith relays the sentiment, presumably voiced by those
opposed to women abolitionists, that “woman ‘can take no part [inthe debate over slavery] without losing something of the modesty
and gentleness which are her most appropriate ornaments.’” Smith
opposes this view in the following sentence: “must woman necessarily
be less gentle because her heart is open to the claims of humanity,or less modest because she feels for the degradation of her enslaved
sisters, and would stretch forth her hand for their rescue?” The leading
tone of this rhetorical question makes it clear that Smith would answer
it with a “no.” Thus, Smith argues that it is possible for women to act
according to humanitarian principles while preserving their femininity.
Choices B, C, and D are incorrect because Smith doesn’t argue that
it is possible for women to adhere to personal morality while being
politically neutral (choice B), contribute to their family’s financial
security while meeting social expectations (choice C), or resist calls for
war while still opposing slavery (choice D).

QUESTION 37

Choice A is the best answer. The previous question asks which
activity Smith argues it is possible for women to engage in. The
answer, that she argues that women can act according to humanitarianprinciples while preserving their femininity, is best supported in thelast sentence of the second paragraph: “must woman necessarily beless gentle because her heart is open to the claims of humanity, orless modest because she feels for the degradation of her enslaved
sisters, and would stretch forth her hand for their rescue?” The leading
tone of this rhetorical question makes it clear that Smith would
answer it with a “no.” In other words, Smith believes that women
can uphold humanitarian principles while maintaining conventional
feminine virtues.
Choices B, C, and D are incorrect because the cited lines don’t support
the answer to the previous question. Instead, they link women’s
conventional domestic concerns with the losses that would be incurredby a war over slavery (choice B), affirm that the potential horrors of516

Answer Explanations | SAT Practice Test #9

war are enough to stir women out of a state of political inactivity(choice C), and equate women’s patriotism with that of male politicalleaders (choice D).

QUESTION 38

Choice C is the best answer. In the first sentence of the thirdparagraph, Smith states “by the Constitution of the United States,
the whole physical power of the North is pledged for the suppressionof domestic insurrections, and should the slaves, maddened byoppression, endeavor to shake off the yoke of the taskmaster, the menof the North are bound to make common cause with the tyrant, andput down, at the point of the bayonet, every effort on the part of theslave, for the attainment of his freedom.” In other words, according to
Smith, if slaves were to revolt, the US Constitution would require that
Northern states help the slave states fight the slaves’ rebellion.
Choices A, B, and D are incorrect because Smith doesn’t argue that
if the slaves were to revolt the US Constitution would require theNorthern states to sever ties with the slave states (choice A), give
shelter to refugees from the slave states (choice B), or provide financial
assistance to the rebelling slaves (choice D).

QUESTION 39

Choice D is the best answer. The word “tyrant” describes a cruel andunfair ruler. It is first used in the first sentence of the third paragraph,when Smith argues that in the event of a slave rebellion in the slavestates, “the men of the North are bound to make common cause withthe tyrant, and put down, at the point of the bayonet, every effort on thepart of the slave, for the attainment of his freedom.” The word occurs
again in the seventh sentence of the last paragraph, when Smithasserts the strength of women’s “aspirations that every inhabitant of
our land may be protected . . . by just and equal laws” so that “the footof the tyrant may no longer invade the domestic sanctuary.” In bothinstances, the word “tyrant” is used to represent slaveholders andtheir allies. Thus, Smith’s use of “tyrant” emphasizes the unjustnessof slavery.
Choice A is incorrect because Smith’s use of the word “tyrant” doesn’t
identify a specific individual as oppressive. Instead, it refers to all
those individuals who profit from and abet the unjust institution ofslavery. Choice B is incorrect because Smith’s use of the word “tyrant”
doesn’t highlight the threat of aggression from abroad. Instead, ithighlights national injustice. Choice C is incorrect because Smith’s
use of the word “tyrant” doesn’t critique the limited roles for womenin antislavery movements. Smith’s use of the word “tyrant” refers toslaveholders and their allies, not those who would discourage women’s
participation in the antislavery movement.

517

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 40

Choice C is the best answer. In the last sentence of the thirdparagraph, Smith argues that the threat of a war precipitated by slavery“is of itself sufficient to arouse the slumbering energies of woman” tospeak out against slavery’s injustice. In other words, women have thepotential to protest slavery, but they have been relatively inactive, or
dormant, up until now. Therefore, the word “slumbering,” as used inthis sentence, most nearly means dormant.
Choices A, B, and D are incorrect because in the context of thepassage, “slumbering” means dormant, not lethargic (choice A),
drowsy (choice B), or unconscious (choice D).

QUESTION 41

Choice A is the best answer. The fifth sentence of the last paragraphposes the following question: “Shall we silently behold the land
which we love with all the heart-warm affection of children, rendereda hissing and a reproach throughout the world, by this system whichis already tolling the death-bell of her decease among the nations?” In
other words, the continuation of slavery in the United States is being
criticized “throughout the world,” such that the existence of slavery
affects the United States by lowering the country’s reputation in theinternational community.
Choice B is incorrect because Smith doesn’t suggest that slavery
affects the United States by leading many women to disavow their
allegiance to the country. Instead, she suggests that it is partly
women’s patriotism that should stir them to protest slavery because
it is lowering the reputation of the United States in the international
community. Choice C is incorrect. Although Smith speaks ominously
in the last paragraph of “the events of the last two years” that are“overclouding the bright prospects of the future,” she doesn’t cite
any current violent conflicts in the country. Choice D is incorrect
because Smith doesn’t suggest that slavery weakens the authorityof the country’s government. Instead, she argues that it damages thecountry’s reputation abroad.

QUESTION 42

Choice C is the best answer. The previous question asks how Smith
most strongly suggests that slavery affects the United States. The
answer, that slavery affects the United States by lowering the country’s
reputation in the international community, is best supported by thefifth sentence of the last paragraph: “Shall we silently behold the land
which we love with all the heart-warm affection of children, rendered ahissing and a reproach throughout the world, by this system which isalready tolling the death-bell of her decease among the nations?”
Choices A, B, and D are incorrect because the cited lines don’t support
the answer to the previous question. Instead, they suggest that
because war affects home life, women are right to concern themselves518

Answer Explanations | SAT Practice Test #9

with the possibility of war (choice A), imply that women have a rightto consider issues that fall outside the domestic sphere (choice B),
and issue a call to action for women to voice condemnation of slavery(choice D).

QUESTION 43

Choice C is the best answer. The first paragraph of Passage 1
presents a quote by biochemist Kim Lewis of Northeastern University:“Pathogens are acquiring resistance faster than we can introduce
new antibiotics, and this is causing a human health crisis.” The
rest of the passage describes Lewis’s research and the experimental
antibiotic called teixobactin that her research has produced. According
to the second paragraph of the passage, teixobactin has “proved
effective at killing off a wide variety of disease-causing bacteria—even
those that have developed immunity to other drugs.” Therefore, thefirst paragraph of Passage 1 primarily serves to identify a problem thatthe research discussed in the passage may help to address.
Choice A is incorrect because although the first paragraph quotes
a claim by Lewis regarding antibiotic resistance, this claim isn’t
developed over the course of Passage 1. Choice B is incorrect because
the claim made in the first paragraph regarding antibiotic resistance
isn’t presented as controversial, nor does Passage 1 attempt to resolve
any scientific controversies. Choice D is incorrect because the claim
made in Paragraph 1 isn’t presented as a theory; moreover, the findings
in Passage 1 support this claim rather than challenge it.

QUESTION 44

Choice D is the best answer. The third paragraph of Passage 1
describes how, historically, the development of antibiotics requires“natural microbial substances,” but this reliance has severe limitations
as only about one percent of these microbial substances can begrown in a laboratory. The author goes on to explain how “the rest,
in staggering numbers, have remained uncultured and of limited use
to medical science, until now.” The paragraph then describes themethod Lewis’s team used to grow teixobactin microorganisms “intheir natural environment where they already have the conditions theyneed for growth.” Therefore, the author of Passage 1 suggests that anadvantage of the method Lewis’s team used to grow microorganisms
is that it allows researchers to make use of soil bacteria that they had
previously been unable to exploit.
Choice A is incorrect because although the author of Passage 1
suggests that Lewis’s team identified the requirements for soil bacteria
to thrive, the team didn’t replicate those features in artificial soil.
Instead, the author suggests in the third and fourth paragraphs ofPassage 1 that they used real soil samples. Choice B is incorrect
because the author of Passage 1 doesn’t suggest that the method
Lewis’s team used to grow microorganisms enabled soil bacteria to
519

PART 4 | Eight Official Practice Tests with Answer Explanations

take in more nutrients than they typically consume in natural settings.
Instead, it can be inferred from the fourth paragraph of the passage
that the bacteria were provided with the same nutrients they consume
in natural settings. Choice C is incorrect because the last paragraph of
Passage 1 explains that it isn’t the method Lewis’s team used to growbacteria but the antibiotic the team created that affects the cell wallsof bacteria.

QUESTION 45

Choice A is the best answer. The previous question asks what
advantage of the method Lewis’s team used to grow microorganisms
is suggested by the author of Passage 1. The answer, that thismethod allows researchers to make use of soil bacteria that they
had previously been unable to exploit, is best supported by the firstthrough third sentences of the third paragraph of Passage 1: “Natural
microbial substances from soil bacteria and fungi have been at the rootof most antibiotic drug development during the past century. But only
about one percent of these organisms can be grown in a lab. The rest,
in staggering numbers, have remained uncultured and of limited use to
medical science, until now.”
Choices B, C, and D are incorrect because the cited lines don’t support
the answer to the previous question. Instead, they describe the gadgetthat Lewis’s team developed to grow microorganisms (choice B),
explain how the team’s technique affects the bacteria (choice C), andoutline how teixobactin attacks harmful bacteria (choice D).

QUESTION 46

Choice D is the best answer. In the first sentence of Passage 2, theauthor outlines the “long . . . suspected” belief that if researchers could“grow more types of bacteria from soil . . . then we might find new natural
antibiotics.” The author then explains how Lewis’s team’s technique that
led to the development of teixobactin employed growing bacteria fromsoil. The author concludes in the last sentence of the first paragraph that
Lewis’s team’s “simple and elegant methodology . . . opens a gateway
to cultivating a wealth of potentially antibiotic-producing bacteria.”
Therefore, the author of Passage 2 would most likely agree with thestatement that the development of teixobactin confirms a long-held belief
about a potential source of new antibiotics.
Choice A is incorrect because the author of Passage 2 wouldn’t likely
agree with the statement that the development of teixobactin reveals
that some antibiotics are effective against gram-negative bacteria.
The author mentions gram-negative bacteria in the third paragraph tohighlight teixobactin’s ineffectiveness in combating it, not to discuss
other antibiotics that are effective against gram-negative bacteria.
Choice B is incorrect because the author wouldn’t likely agree with thestatement that the development of teixobactin shows that conventional
methods can still yield new types of antibiotics. Instead, the author
520

Answer Explanations | SAT Practice Test #9

contends that the unconventional method used to produce teixobactin
may yield new types of antibiotics. Choice C is incorrect because theauthor wouldn’t likely agree with the statement that the developmentof teixobactin casts doubt on the practicality of searching for new
antibiotics in exotic environments. Rather, in the first paragraph of
Passage 2, the author states that exotic environments might yield
new antibiotics.

QUESTION 47

Choice C is the best answer. In the first sentence of the last paragraphof Passage 2, the author expresses reservations about the immediate
usefulness of teixobactin: “So, what are my caveats? Well, I see three.
First, teixobactin isn’t a potential panacea. . . . Secondly, scaling tocommercial manufacture will be challenging. . . . And, thirdly . . .
teixobactin now faces the long haul of clinical trials.” The author uses
the word “caveats” to introduce skeptical comments about teixobactin’svalue. Thus, the word “caveats,” as used in the first sentence of thelast paragraph of Passage 2, most nearly means misgivings.
Choices A, B, and D are incorrect because in the context of thepassage, “caveats” means misgivings, not exceptions (choice A),
restrictions (choice B), or explanations (choice D).

QUESTION 48

Choice A is the best answer. In the last paragraph of Passage 2, theauthor expresses reservations regarding teixobactin. One of thesereservations is that the drug “now faces the long haul of clinical
trials” before teixobactin can be made available for consumers. These
clinical trials will be used to discover “what dose you can safely givethe patient . . . if it cures infections, and . . . to compare its efficacy tothat of ‘standard of care treatment,’” and are “going to take five years
and £500 million.” Thus, the author uses the phrase “five years and£500 million” primarily to emphasize the scale of the effort needed tomake teixobactin available for consumer use.
Choices B, C, and D are incorrect because the author of Passage 2
uses the phrase “five years and £500 million” as a reference to the timeand financial commitment that will be required to make teixobactin
available to the public. That being the case, the phrase doesn’t imply
criticism of the level of funding that the government has committed to
teixobactin development (choice B), address the amount of time andmoney that has already been spent researching teixobactin (choice C),
or compare the amount of money spent developing teixobactin with theamount spent developing other antibiotics (choice D).

QUESTION 49

Choice A is the best answer. Passage 1 discusses research conductedby biochemist Kim Lewis. As described in the second paragraph ofthe passage, this research explored “a new way to tap the powers of521

PART 4 | Eight Official Practice Tests with Answer Explanations

soil microorganisms” in the laboratory and led to the development of
teixobactin, a promising new drug that could “function effectively for
decades,” thereby addressing the problem of pathogens’ resistance toantibiotics. The author of Passage 2 critiques the research describedin Passage 1. In the first paragraph of Passage 2, the author declaresthat the methodology Lewis and others developed “is their mostimportant finding . . . for it opens a gateway to cultivating a wealth ofpotentially antibiotic-producing bacteria.” However, teixobactin “is lessexciting” to the author of Passage 2 because it has proved ineffectiveat combating certain types of bacteria and large investments of timeand money will be needed before it can be made available to the publicat large, according to the second and third paragraphs of Passage 2.
Therefore, the best description of the relationship between Passage 1
and Passage 2 is that Passage 2 offers an evaluation of the significanceof the research discussed in Passage 1.
Choice B is incorrect because Passage 2 doesn’t suggest amodification to the methodology described in Passage 1. Instead, theauthor of Passage 2 embraces the “simple and elegant” methodology
described in Passage 1. Choice C is incorrect because Passage 2
doesn’t use concrete examples to illustrate concepts considered in
Passage 1. Instead, it evaluates the significance of the research.
Choice D is incorrect because Passage 2 doesn’t take a dismissive
stance regarding the findings mentioned in Passage 1. The authorof Passage 2 endorses the methodology described in Passage 1, andconcedes that teixobactin “doesn’t look bad,” while outlining somereservations about the drug’s value.

QUESTION 50

Choice B is the best answer. The first paragraph of Passage 1 quotes
biochemist Kim Lewis of Northeastern University: “Pathogens are
acquiring resistance faster than we can introduce new antibiotics, andthis is causing a human health crisis.” However, research conductedby Lewis has produced a drug called teixobactin, which has “proved
effective at killing off a wide variety of disease-causing bacteria—even
those that have developed immunity to other drugs,” according to thesecond sentence of the second paragraph of Passage 1. Similarly, inthe third sentence of the second paragraph of Passage 2, the author of
the passage states that teixobactin “killed the tuberculosis bacterium,
which is important because there is a real problem with resistanttuberculosis in the developing world.” Therefore, both passages makethe point that teixobactin could be useful in combating infections thatare no longer responding to treatment with other antibiotics.
Choice A is incorrect because Passage 1 outlines the methodology
used to produce teixobactin but doesn’t offer it as a model for future
development of antibiotics produced in laboratory environments.
Passage 2 suggests that future development of antibiotics may draw
on the methodology that Lewis and others developed, but the passage
doesn’t go so far as to suggest that teixobactin could be used to522

Answer Explanations | SAT Practice Test #9

standardize this development. Choices C and D are incorrect because
neither passage makes the point that teixobactin could be useful incontrolling the spread of pathogenic soil fungi (choice C) or in shaping
a new method of studying the effectiveness of antibiotics (choice D).

QUESTION 51

Choice C is the best answer. According to the last sentence of thefifth paragraph of Passage 1, “Mice infected with bacteria that cause
upper respiratory tract infections . . . were treated with teixobactin, andthe drug knocked out the infections with no noticeable toxic effects.”
The second paragraph of Passage 2 explains that teixobactin wastested in a laboratory and killed gram-positive bacteria, but, according
to the fourth sentence of the third paragraph, it “doesn’t kill the Gramnegative opportunists as it is too big to cross their complex cell wall.”
Therefore, since teixobactin was not successful in eradicating gramnegative bacteria as stated in Passage 2, this information best supports
the conclusion that the mice described in the experiment in Passage 1
had upper respiratory tract infections that were likely not caused bygram-negative bacteria since these infections were successfully treatedby teixobactin.
Choices A, B, and D are incorrect because no information in Passage 2
supports the conclusion that the mice in the experiment described in
Passage 1 were less susceptible to subsequent upper respiratory tract
infections due to exposure to teixobactin (choice A), the gram-positivebacteria enhanced the effectiveness of teixobactin against the upper
respiratory tract infections in the mice (choice B), or the teixobactin
attacked the proteins of the bacteria that caused the upper respiratory
tract infections in the mice.

QUESTION 52

Choice D is the best answer. The previous question asks whichconclusion about the mice in the experiment described in Passage 1
is best supported by information in Passage 2. The answer, that their
upper respiratory tract infections were likely not caused by gramnegative bacteria, is best supported by the fourth sentence of thethird paragraph of Passage 2: “[Teixobactin] doesn’t kill the Gramnegative opportunists as it is too big to cross their complex cell wall.”
Choices A, B, and C are incorrect because the cited lines don’t support
the answer to the previous question. Instead, they provide a historicalbackground to Lewis’s cultivation of soil bacteria (choice A), praise
the methodology used by Lewis’s team and others (choice B), andintroduce an evaluation of teixobactin (choice C).

523

PART 4 | Eight Official Practice Tests with Answer Explanations

Section 2: writing and language Test
QUESTION 1

Choice B is the best answer. The verb “watch” clearly and concisely
indicates that scientists can view underwater volcanic eruptions “viaremotely operated vehicles.”
Choices A, C, and D are incorrect because they’re repetitive.
“Observe,” “see,” and “visually” unnecessarily reiterate the idea thatscientists can view underwater volcanic eruptions.

QUESTION 2

Choice B is the best answer. Sentence 5 should be placed after
sentence 1. The phrase “at that depth” at the beginning of sentence 5
refers to the statement in sentence 1 that NW Rota-1’s summit is located“more than 1,700 feet under the ocean’s surface.” Furthermore, sentence 5
leads into sentence 2, which explains what scientists were able todetermine about the volcano’s growth from remotely operated vehicles.
Choices A, C, and D are incorrect because placing sentence 5
anywhere in the paragraph other than after sentence 1 would create an
illogical, confusing paragraph.

QUESTION 3

Choice A is the best answer. The adverb “nevertheless” correctly
indicates that despite the fact that sunlight doesn’t reach NW Rota-1,
the bacteria there have adapted to the “perpetually dark environment”
and “use hydrogen sulfide instead of sunlight” for energy.
Choices B, C, and D are incorrect because they don’t indicate thetrue relationship between the two independent clauses. “Afterward”
indicates that one event happens after another. “Furthermore”
suggests that additional information about what has been said earlier
in the sentence will follow. “Similarly” indicates that a comparison is
being made.

QUESTION 4

Choice C is the best answer. The plural pronoun “them” agrees in
number with the plural antecedent “bacteria.”
Choices A, B, and D are incorrect because they’re singular pronouns
that don’t agree in number with the plural antecedent “bacteria.”

QUESTION 5

Choice D is the best answer. The conjunction “and” followed by “otherchemicals” results in a sentence with a parallel series of nouns.
Choices A, B, and C are incorrect because they don’t maintain thesentence’s parallel structure, and they unnecessarily repeat a form of
the verb “remove.”524

Answer Explanations | SAT Practice Test #9

QUESTION 6

Choice C is the best answer. The dashes after “shrimp” and “Hawaii”
are used correctly to set off the nonessential information between them.
Choices A and B are incorrect because neither a comma nor asemicolon can be used with a dash to set off nonessential information.
Choice D is incorrect because punctuation, in this case a dash, isneeded after “Hawaii” to finish setting off the nonessential information.

QUESTION 7

Choice D is the best answer. This choice’s reference to “predators”
most effectively sets up the sentence that follows, which explains that,as adults, the previously unknown species of shrimp feeds on the
Loihi shrimp.
Choices A, B, and C are incorrect because they don’t effectively set up
the information in the sentence that follows. The following sentence
doesn’t discuss the idea that the other species of shrimp is able toadapt to its noxious environment. Additionally, it doesn’t address
the idea that scientists don’t yet understand the adaptations of theshrimp or that their unusual ecosystem also includes crabs, limpets,and barnacles.

QUESTION 8

Choice A is the best answer. This choice most effectively combines
the sentences at the underlined portion by creating a compound
predicate using two parallel, singular, present tense verbs(“condenses” and “leaves”) to show that as the steam condenses only
“carbon dioxide bubbles and droplets of molten sulfur” are left.
Choices B, C, and D are incorrect because they don’t effectively
combine the sentences. The resulting sentences aren’t concise, and theverbs aren’t parallel.

QUESTION 9

Choice D is the best answer. This choice results in a logicalcomparison between the water near NW Rota-1 and stomach acid.
Choices A and B are incorrect because the demonstrative pronouns“that” and “those” don’t have clear antecedents, leaving unclear what
the water near NW Rota-1 is being compared to. Choice C is incorrect
because it unnecessarily repeats the word “acid,” resulting in a
nonsensical expression (“the acid from stomach acid”).

QUESTION 10

Choice C is the best answer. The singular possessive noun “world’s”
is used correctly to indicate that the plural noun “oceans” belongs to
one world.

525

PART 4 | Eight Official Practice Tests with Answer Explanations

Choice A is incorrect because “worlds’” is a plural possessive noun,
and there is only one world being referred to. Furthermore, thepossessive noun “ocean’s” is incorrect because nothing belongs to theocean in this sentence. Choice B is incorrect because “oceans’” is apossessive noun, and nothing belongs to “oceans” in this sentence.
Choice D is incorrect because “worlds” is a plural noun, and this noun
needs to be the singular possessive noun “world’s” to show that theoceans belong to one world.

QUESTION 11

Choice A is the best answer. The writer should make the revisionbecause it shows the relevance of the sentence about rising carbon
dioxide levels in Earth’s atmosphere to the paragraph’s point about theincreasing acidity of the world’s oceans.
Choice B is incorrect because the revision doesn’t help readers tounderstand why organisms near NW Rota-1 evolved the way they did.
Choices C and D are incorrect because the revision should be made.
The revision doesn’t repeat information, and it does contribute to theparagraph’s main idea. Furthermore, it doesn’t add an irrelevant detailthat interrupts the discussion of oceanic life-forms.

QUESTION 12

Choice C is the best answer. The comma after “ridership” is usedcorrectly to separate the dependent clause that begins with the word
“while” from the independent clause that follows “ridership.”
Choice A is incorrect because the conjunction “but” can’t join adependent clause to an independent clause. Choice B is incorrect
because the conjunctions “and while” create a second dependent
clause, but an independent clause is needed to make the sentencecomplete. Choice D is incorrect because a semicolon can’t be usedin this way to separate an introductory dependent clause from an
independent clause.

QUESTION 13

Choice B is the best answer. This choice is the most effective because
it doesn’t repeat the word “people.” Furthermore, this choice’s use of
the active voice, which indicates that “more people” (the subject of thesentence) use public transportation, eliminates unnecessary wording.
Choices A and C are incorrect because they unnecessarily repeat
the noun “people.” Choice D is incorrect because the use of the passive
voice, which changes the subject of the sentence from “more people”
to “using public transportation,” creates a wordy sentence.

526

Answer Explanations | SAT Practice Test #9

QUESTION 14

Choice B is the best answer. The colon correctly introduces
information that illustrates what has come before it. The independent
clause that follows the colon indicates that “car traffic in Tallinn was
down less than 3 percent,” which supports the statement before thecolon that “car use in Tallinn has only slightly declined.”
Choice A is incorrect because the semicolon awkwardly joins an
independent clause with the dependent clause that follows. Choice C
is incorrect because it creates a comma splice. Choice D is incorrect
because it creates a sentence fragment after the period.

QUESTION 15

Choice D is the best answer. “The policy” clearly indicates what wasenacted. The passage indicates that “car traffic in Tallinn was down
less than 3 percent” since the policy of fare-free rides was enacted.
Choices A, B, and C are incorrect because the pronouns in thesechoices don’t have clear antecedents.

QUESTION 16

Choice A is the best answer. This choice best introduces theparagraph; the phrase “devastating effect” sets up the paragraph’s
discussion of how fare-free systems can negatively impact a city’stransportation budget.
Choices B, C, and D are incorrect because they don’t introduce theparagraph’s topic, which is the devastating effects of a fare-freesystem on a city’s budget. The paragraph doesn’t focus on changes
in service, negative environmental impact, or increased crowding on
public transportation.

QUESTION 17

Choice C is the best answer. The comma after “savings” andthe conjunction “but” are used correctly to connect the two
independent clauses.
Choices A and B are incorrect because they each create a comma
splice. Choice D is incorrect because the conjunction “and” signals
additional information rather than the needed contrast.

QUESTION 18

Choice D is the best answer. The expression “overly optimistic” isconsistent with the formal tone of the passage.
Choices A, B, and C are incorrect. While “way too sunny,” “looking
too much on the bright side,” and “pretty upbeat” all convey optimism,
they’re colloquial expressions that don’t fit the formal tone ofthe passage.

527

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 19

Choice C is the best answer. This choice provides an accurateinterpretation because the chart indicates that the projected total
additional operating costs for implementing a fare-free policy in
San Francisco, CA, would be $184 million per year.
Choices A, B, and D are incorrect because they don’t accuratelyinterpret the information provided in the chart for San Francisco, CA.
The chart projects a cost of $112 million in lost fares, not a deficit of$72 million per year in lost fares (choice A) or a savings of $112 million
from lost fares (choice B). The chart projects a cost of $72 million peryear to add fare-free service, not a savings of $72 million (choice D).

QUESTION 20

Choice C is the best answer. The sentence shouldn’t be added
because the fact that Eugene, OR, “would lose only $5 million” doesn’t
support the writer’s argument that fare-free systems cause large
financial losses to governments.
Choices A and B are incorrect. The sentence shouldn’t be added
because the fact that Eugene, OR, would lose only $5 million in fares
doesn’t support the writer’s argument against fare-free systems.
Furthermore, it doesn’t reinforce any claim made earlier in theparagraph by advocates of fare-free policies. Choice D is incorrect
because the sentence doesn’t contradict any point made earlier in theparagraph about fare collection.

QUESTION 21

Choice B is the best answer. The present indicative verb “do [not]have” is consistent in tense and mood with the present indicative verb
“can go” earlier in the sentence.
Choice A is incorrect because “would [not] have had” is a perfectconditional verb. Choice C is incorrect because “did [not] have” is apast indicative verb. Choice D is incorrect because “will [not] have” is a
future indicative verb.

QUESTION 22

Choice D is the best answer. This choice provides the best conclusion
to the passage, which argues that fare-free transportation policies“have not been found to be an effective way to address traffic
problems” and “may result in serious budget shortfalls.”
Choices A, B, and C are incorrect because they don’t provide the best
conclusion to the passage. Choice A is too narrowly focused, andchoices B and C make claims that aren’t supported by information in
the passage.

528

Answer Explanations | SAT Practice Test #9

QUESTION 23

Choice B is the best answer. The singular third person pronoun “it”
correctly refers to the singular antecedent “digital camera.”
Choice A is incorrect because the plural pronoun “they” doesn’t agree
in number with the singular antecedent “digital camera.” (It wouldn't
make sense here to assume that “they” refers to “professional
photographers,” as there’s no clear indication that the photographers
referred to used the earliest digital cameras.) Choice C is incorrect
because the indefinite pronoun “one” doesn’t refer to a specific noun.
Choice D is incorrect because the personal pronouns “he or she” referto people, not things.

QUESTION 24

Choice B is the best answer. To make the paragraph most logical, the
new sentence “Why wouldn’t they?” should be placed after sentence 2.
The pronoun “they” in the new sentence refers to the “vast majority”
of professional photographers mentioned in sentence 2. Furthermore,
the two sentences that follow the new sentence answer the questionof why photographers would trade film for digital cameras by statingthat the latest digital cameras take pictures that are “crisp,” “bright,”
and “sharp.”
Choices A, C, and D are incorrect because placing the new sentence
anywhere in the paragraph other than after sentence 2 would create an
illogical and confusing paragraph.

QUESTION 25

Choice B is the best answer. The new sentence should be added
because its reference to “several intricate steps” sets up the process of
wet plate photography discussed in the rest of the paragraph.
Choice A is incorrect. The sentence should be added, but it doesn’treiterate the previous paragraph’s main idea. Choices C and D areincorrect because the sentence should be added. The new sentence
doesn’t blur the paragraph’s focus on the dangers of developing
wet plate photographs. It also doesn’t offer an opinion: while“labor-intensive” can be interpreted as an opinion, the description of
the steps is factual.

QUESTION 26

Choice D is the best answer. The plural possessive pronoun “their”
agrees in number with the plural antecedent “photographers” andcorrectly indicates that the subjects belong to the photographers.
Choice A is incorrect because “it’s” is a contraction for “it is” anddoesn’t make sense in the sentence. Choice B is incorrect because “its”
is a singular possessive pronoun and doesn’t agree in number withthe plural antecedent “photographers.” Choice C is incorrect because“there” isn’t a possessive pronoun.
529

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 27

Choice A is the best answer. The coordinating conjunction “so” isused correctly to indicate that because dried collodion is unusable, aphotographer has to work quickly to develop the film once the photois taken.
Choices B, C, and D are incorrect because they don’t convey theintended cause-and-effect relationship between the two independent
clauses. “But” (choice B) indicates that an exception or contrast towhat was said previously will follow. “And” (choice C) suggests thatthe two clauses indicate separate ideas instead of a cause-and-effectrelationship. “For” (choice D), used as a conjunction, means“because.” If used in this sentence, “for” would indicate that driedcollodion is unusable because the photographer must quickly develop
the photograph.

QUESTION 28

Choice D is the best answer. The word “mere” most effectively
suggests that the photographer has only a very brief time to develop
wet plate photographs.
Choices A, B, and C are incorrect because they don’t accomplish thewriter’s goal of emphasizing how quickly wet plate photographers mustwork. “Nominal” isn’t idiomatic when referring to a short amount oftime. “A few” and “a matter of” can be used to describe time, but neither
choice emphasizes how quickly wet plate photographers have to work.

QUESTION 29

Choice B is the best answer. The adverb “finally” correctly indicatesthat the last step in the process of wet plate photography is to coat thephoto with a protective finish.
Choices A, C, and D are incorrect because they don’t indicate that the
final step in a process will follow. “In conclusion” is used to introduce
a summary of what has previously been said. “Thus” indicates that a
result of what has been previously stated will follow. “Nevertheless” isused to introduce a contrast to what has been stated earlier.

QUESTION 30

Choice D is the best answer. No punctuation is needed in the sentence
except for a period.
Choice A is incorrect because the parentheses indicate that the
information between them could be deleted without changing themeaning of the sentence. In this sentence, the information in theparentheses contains the direct object of the verb “give” and isessential. Choice B is incorrect because the dash wrongly indicatesthat the information following is being emphasized. Choice C isincorrect because the commas indicate that the information between
them is nonessential and could be deleted.
530

Answer Explanations | SAT Practice Test #9

QUESTION 31

Choice A is the best answer. The present tense verb “swirl” isconsistent with the other present tense verbs in the paragraph’s
description of wet plate photographs.
Choices B, C, and D are incorrect because the tenses of these choices
are inconsistent with the present tense verbs in the paragraph’s
description of wet plate photographs. “Will have swirled” (choice B)
is a future perfect tense verb. “Have swirled” (choice C) is a present
perfect tense verb. “Swirled” (choice D) is a simple past tense verb.

QUESTION 32

Choice D is the best answer. This choice is clear and concise anddoesn’t unnecessarily repeat the idea that long exposure time cancause parts of a subject to disappear in a photo.
Choices A, B, and C are incorrect because they’re repetitive. The
previous sentence already mentions the “long exposures,” and thisnoun phrase doesn’t need to be repeated.

QUESTION 33

Choice A is the best answer. The reference to “nineteenth-century
wave riders” accomplishes the writer’s goal of highlighting the contrast
between present-day photographer Joni Sternbach’s nineteenth-century
techniques and her contemporary subjects.
Choices B, C, and D are incorrect because they don’t highlight acontrast between Sternbach’s techniques and her subjects. The
descriptions “ordinary people,” “surfers,” and people “from all walks oflife” don’t clearly allude to the old style of her photographic techniques
and, therefore, don’t offer a contrast to her subjects who wear “modern
board shorts and bikinis.”

QUESTION 34

Choice A is the best answer. The revision should be made because
the passage is about how a team of urban archaeologists uncovered
the history of New York City’s South Street Seaport, and this revision
helps explain the job of urban archaeologists.
Choice B is incorrect because, although the revision should be made,it doesn’t identify the characteristics that make “cities worthy ofarchaeological study.” Choices C and D are incorrect because therevision should be made. Neither the kinds of artifacts that urban
archaeologists find nor how excavation benefits historical study
explains what urban archaeologists do.

QUESTION 35

Choice C is the best answer. The singular verb “is required” agrees in
number with the singular subject “project.”531

PART 4 | Eight Official Practice Tests with Answer Explanations

Choices A, B, and D are incorrect because the plural verbs “arerequired,” “have been required,” and “were required” don’t agree in
number with the singular subject “project.”

QUESTION 36

Choice D is the best answer. This choice is clear and concise and doesn’t
repeat the idea of “possibility” already mentioned in the sentence.
Choices A and B are incorrect because the words “possible” and“potentially” repeat the idea of “possibility” mentioned earlier in thesentence. Choice C is incorrect because “it is necessary that” repeats
the idea mentioned later in the sentence that “an urban archaeologist
must be consulted.”

QUESTION 37

Choice B is the best answer. The adverb “though” correctly conveys
a contrast between the facts that the work continued and the team
faced obstacles.
Choices A, C, and D are incorrect because they don’t indicate thetrue relationship between the progression of the team’s work and the
obstacles. “Therefore” suggests that because the work continued,
the team faced obstacles. “Meanwhile” is redundant: the dependent
clause “as the work continued” already implies that the work was
happening when obstacles emerged. “Similarly” suggests that acomparison is being made.

QUESTION 38

Choice D is the best answer. No punctuation is needed between theverb “halted” and the prepositional phrase “by stormy weather and thediscovery of toxic materials underground” that follows it.
Choices A, B, and C are incorrect because each introduces unnecessarypunctuation between the verb and the prepositional phrase.

QUESTION 39

Choice C is the best answer. The noun “pedestrians” is parallel inform to the nouns “vehicles” and “car horns.”
Choices A, B, and D are incorrect because the repetition of “noise” inchoices A and B and the inclusion of the pronoun “that” (which stands
in for “noise”) in choice D violate the parallel structure of the series ofnouns (“construction vehicles,” “car horns,” “pedestrians”) serving as
the objects of the preposition “of.”QUESTION 40

Choice C is the best answer. The comma is used correctly to separate
the independent clause from the participial phrase that begins
with “including.”
532

Answer Explanations | SAT Practice Test #9

Choice A is incorrect because the period after “site” results in arhetorically poor fragment. Choice B is incorrect because the comma
after “site” creates a comma splice. Choice D is incorrect because asemicolon can’t be used in this way to connect an independent clauseto a participial phrase.

QUESTION 41

Choice C is the best answer. This idea of “public utility planning andinfrastructure development” best sets up the example that follows
about how colonial-era New Yorkers secured fresh drinking water.
Choices A, B, and D are incorrect because they don’t set up thediscussion of colonial-era New Yorkers’ public utility planning andinfrastructure development. The example that follows doesn’t deal
with construction materials, hospitality rituals, or the financing of
construction projects.

QUESTION 42

Choice A is the best answer. The word “effort” is consistent with theformal style and tone of the passage.
Choices B, C, and D are incorrect because they don’t maintain theformal style and tone of the passage. Choices B and C are colloquial,
and choices B and D are exaggerations that are inconsistent with thepassage’s informative style.

QUESTION 43

Choice D is the best answer. The subject of the sentence, “urban
archaeologists,” clearly identifies who makes discoveries and tells thestory of a city’s history.
Choices A and B are incorrect because the pronouns “they” and “we”
don’t have clear antecedents. Choice C is incorrect because it isn’t
true. “Colonial-era New Yorkers” don’t make the discoveries or tell thestories to which the sentence refers.

QUESTION 44

Choice C is the best answer. This choice accomplishes the goal ofidentifying the broad impact of the urban archaeological team’s workby mentioning that excavation “makes New York City’s history real.”
Choices A, B, and D are incorrect because they don’t illustrate thebroad impact of the team’s work. Loorya’s references to one of her
favorite things about her work (choice A), New York City construction(choice B), and the archaeological technique of monitoring (choice D)
don’t provide an effective concluding statement about her team’s impact.

533

PART 4 | Eight Official Practice Tests with Answer Explanations

Section 3: Math Test – No Calculator
QUESTION 1

Choice B is correct. Multiplying both sides of the first equation in
the system by 2 yields 4x − 2y = 16. Adding 4x − 2y = 16 to the second
equation in the system yields 5x = 20. Dividing both sides of 5x = 20
by 5 yields x = 4. Substituting 4 for x in x + 2y = 4 yields 4 + 2y = 4.
Subtracting 4 from both sides of 4 + 2y = 4 yields 2y = 0. Dividing bothsides of this equation by 2 yields y = 0. Substituting 4 for x and 0 for yin the expression x + y yields 4 + 0 = 4.
Choices A, C, and D are incorrect and may result from various
computation errors.

QUESTION 2

Choice A is correct. Since (x 2 − x) is a common term in the original
expression, like terms can be added: 2(x 2 − x) + 3(x 2 − x) = 5(x 2 − x).
Distributing the constant term 5 yields 5x 2 − 5x.
Choice B is incorrect and may result from not distributing thenegative signs in the expressions within the parentheses. Choice C
is incorrect and may result from not distributing the negative signs
in the expressions within the parentheses and from incorrectly
eliminating the x 2-term. Choice D is incorrect and may result fromincorrectly eliminating the x-term.

QUESTION 3

Choice D is correct. To find the slope and y-intercept, the given
equation can be rewritten in slope-intercept form y = mx + b, wherem represents the slope of the line and b represents the y-intercept. The
given equation 2y − 3x = −4 can be rewritten in slope-intercept form by
first adding 3x to both sides of the equation, which yields 2y = 3x − 4.
Then, dividing both sides of the equation by 2 results in the equation
33
y = ​  — x − 2. The coefficient of x, ​  — ​2
2positive, and the constant term, −2, is the y-intercept of the graph andis negative. Thus, the graph of the equation 2y − 3x = −4 has a positive
slope and a negative y-intercept.
Choice A is incorrect and may result from reversing the values ofthe slope and the y-intercept. Choices B and C are incorrect and may
result from errors in calculation when determining the slope andy-intercept values.

QUESTION 4

Choice A is correct. It’s given that the front of the roller-coastercar starts rising when it’s 15 feet above the ground. This initial heightof 15 feet can be represented by a constant term, 15, in an equation.
Each second, the front of the roller-coaster car rises 8 feet, which can534

Answer Explanations | SAT Practice Test #9

be represented by 8s. Thus, the equation h = 8s + 15 gives the height,
in feet, of the front of the roller-coaster car s seconds after it starts
up the hill.
Choices B and C are incorrect and may result from conceptual errors
in creating a linear equation. Choice D is incorrect and may result
from switching the rate at which the roller-coaster car rises with its
initial height.

QUESTION 5

Choice C is correct. Since the variable h represents the number ofhours a job took, the coefficient of h, 75, represents the electrician’s
charge per hour, in dollars, after an initial fixed charge of $125.
It’s given that the electrician worked 2 hours longer on Ms. Sanchez’s
job than on Mr. Roland’s job; therefore, the additional charge for
Ms. Sanchez’s job is $75 × 2 = $150.
Alternate approach: The amounts the electrician charged for
Mr. Roland’s job and Ms. Sanchez’s job can be expressed in terms of t.
If Mr. Roland’s job took t hours, then it cost 75t + 125 dollars.
Ms. Sanchez’s job must then have taken t + 2 hours, so it cost
75(t + 2) + 125 = 75t + 275 dollars. The difference between the twocosts is (75t + 275) – (75t + 125) = $150.
Choice A is incorrect. This is the electrician’s charge per hour, notthe difference between what Ms. Sanchez was charged and what
Mr. Roland was charged. Choice B is incorrect. This is the fixed charge
for each job, not the difference between the two. Choice D is incorrect
and may result from finding the total charge for a 2-hour job.

QUESTION 6

Choice B is correct. The ratio of the lengths of two arcs of a circle
is equal to the ratio of the measures of the central angles that subtend
the arcs. It’s given that arc ​​ is subtended by a central angle withmeasure 100°. Since the sum of the measures of the angles about apoint is 360°, it follows that arc ​​ is subtended by a central angle
with measure 360° − 100° = 260°. If s is the length of arc ​​s must satisfy the ratio ​  ​. Reducing the fraction ​  ​to its
13
s —
_
​ 5π
= 5
simplest form gives ​  ​13s —_of ​ 5π= 5  ​by 5π yields s = 13π.
Choice A is incorrect. This is the length of an arc consisting ofexactly half of the circle, but arc ​​ is greater than half of the circle.
Choice C is incorrect. This is the total circumference of the circle.
Choice D is incorrect. This is half the length of arc ​​full length.

535

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 7

Choice D is correct. Multiplying both sides of the given equation
by x yields 160x = 8. Dividing both sides of the equation 160x = 8 by
8
8
1
160 results in x = ​  — ​. Reducing ​  — ​to its simplest form gives x = — ​,
160
160
20
or its decimal equivalent 0.05.
Choice A is incorrect and may result from multiplying, instead ofdividing, the left-hand side of the given equation by 160. Choice B
is incorrect and may result from a computational error. Choice C is1
incorrect. This is the value of x​  _ ​QUESTION 8

Choice C is correct. Applying the distributive property ofmultiplication to the right-hand side of the given equation gives(3x + 15) + (5x − 5), or 8x + 10. An equation in the form cx + d = rx + s
will have no solutions if c = r and d ≠ s. Therefore, it follows that theequation 2ax − 15 = 8x + 10 will have no solutions if 2a = 8, or a = 4.
Choice A is incorrect. If a = 1, then the given equation could be written
as 2x − 15 = 8x + 10. Since 2 ≠ 8, this equation has exactly one solution.
Choice B is incorrect. If a = 2, then the given equation could be written
as 4x − 15 = 8x + 10. Since 4 ≠ 8, this equation has exactly one solution.
Choice D is incorrect. If a = 8, then the given equation could be written as
16x − 15 = 8x + 10. Since 16 ≠ 8, this equation has exactly one solution.

QUESTION 9

Choice B is correct. A solution to the system of three equations is
any ordered pair (x, y) that is a solution to each of the three equations.
Such an ordered pair (x, y) must lie on the graph of each equation in
the xy-plane; in other words, it must be a point where all three graphsintersect. The graphs of all three equations intersect at exactly one
point, (−1, 3). Therefore, the system of equations has one solution.
Choice A is incorrect. A system of equations has no solutions when
there is no point at which all the graphs intersect. Because the graphsof all three equations intersect at the point (−1, 3), there is a solution.
Choice C is incorrect. The graphs of all three equations intersect
at only one point, (−1, 3). Since there is no other such point, there
cannot be two solutions. Choice D is incorrect and may result fromcounting the number of points of intersection of the graphs of any two
equations, including the point of intersection of all three equations.

QUESTION 10

Choice C is correct. If the equation is true for all x, then theexpressions on both sides of the equation will be equivalent.
Multiplying the polynomials on the left-hand side of the equation
gives 5ax 3 − abx 2 + 4ax + 15x 2 − 3bx + 12. On the right-hand side ofthe equation, the only x 2-term is −9x 2. Since the expressions on both536

Answer Explanations | SAT Practice Test #9

sides of the equation are equivalent, it follows that −abx 2 + 15x 2 = −9x 2,
which can be rewritten as (−ab + 15)x 2 = −9x 2. Therefore, −ab + 15 = −9,
which gives ab = 24.
Choice A is incorrect. If ab = 18, then the coefficient of x 2 on the left-handside of the equation would be −18 + 15 = −3, which doesn’t equal
the coefficient of x 2, −9, on the right-hand side. Choice B is incorrect. If
ab = 20, then the coefficient of x 2 on the left-hand side of the equation
would be −20 + 15 = −5, which doesn’t equal the coefficient of x 2, −9, on
the right-hand side. Choice D is incorrect. If ab = 40, then the coefficientof x 2 on the left-hand side of the equation would be −40 + 15 = −25,
which doesn’t equal the coefficient of x 2, −9, on the right-hand side.

QUESTION 11

Choice B is correct. The right-hand side of the given equation, ​  ​,
x
can be rewritten as x. Multiplying both sides of the equation _ ​ = x
x−3
by x − 3 yields x = x(x − 3). Applying the distributive property ofmultiplication to the right-hand side of the equation x = x(x − 3)yields x = x 2 − 3x. Subtracting x from both sides of this equation yields
0 = x 2 − 4x. Factoring x from both terms of x 2 − 4x yields 0 = x(x − 4).
By the zero product property, the solutions to the equation 0 = x(x − 4)are x = 0 and x − 4 = 0, or x = 4. Substituting 0 and 4 for x in the given
equation yields 0 = 0 and 4 = 4, respectively. Since both are true
statements, both 0 and 4 are solutions to the given equation.
Choice A is incorrect and may result from a sign error. Choice C isincorrect and may result from an error in factoring. Choice D is incorrect
and may result from not considering 0 as a possible solution.

QUESTION 12

Choice D is correct. The original expression can be combined
into one rational expression by multiplying the numerator anddenominator of the second term by the denominator of the first term:
12x + 1 ​ ​  ​. This​  — + 5 ​  _ ​  , which can be rewritten as ​ 2x + 12x + 1expression is now the sum of two rational expressions with a common()

denominator, and it can be rewritten as ​ 
 ​ ​ 
 ​ ​ 
 ​.
Choice A is incorrect and may result from a calculation error. Choice B isincorrect and may be the result of adding the denominator of the first term
to the second term rather than multiplying the first term by the numerator
and denominator of the second term. Choice C is incorrect and may result
from not adding the numerator of ​  ​to the numerator of ​  ​.

QUESTION 13

Choice A is correct. The equation of a parabola in vertex form isf(x) = a(x − h)2 + k, where the point (h, k ) is the vertex of the parabola
and a is a constant. The graph shows that the coordinates of the vertex

537

PART 4 | Eight Official Practice Tests with Answer Explanationsare (3, 1), so h = 3 and k = 1. Therefore, an equation that defines f canbe written as f(x) = a(x − 3)2 + 1. To find a, substitute a value for x andits corresponding value for y, or f(x). For example, (4, 5) is a point on
the graph of f. So a must satisfy the equation 5 = a(4 − 3)2 + 1, which
can be rewritten as 4 = a(1)2, or a = 4. An equation that defines f istherefore f(x) = 4(x − 3)2 + 1.
Choice B is incorrect and may result from a sign error when writing theequation of the parabola in vertex form. Choice C is incorrect and may
result from omitting the constant a from the vertex form of the equationof the parabola. Choice D is incorrect and may result from a sign error
when writing the equation of the parabola in vertex form as well as
by miscalculating the value of a.

QUESTION 14

Choice B is correct. The solutions of the first inequality, y ≥ x + 2, lie
on or above the line y = x + 2, which is the line that passes through(−2, 0) and (0, 2). The second inequality can be rewritten in slopeintercept form by dividing the second inequality, 2x + 3y ≤ 6, by 3 on
both sides, which yields ​ , and then subtracting ​  from both2sides, which yields y ≤ − — x + 2. The solutions to this inequality lie on
3
2
or below the line y = − — x + 2, which is the line that passes through3(0, 2) and (3, 0). The only graph in which the shaded region meetsthese criteria is choice B.
Choice A is incorrect and may result from reversing the inequality signin the first inequality. Choice C is incorrect and may result from reversing
the inequality sign in the second inequality. Choice D is incorrect andmay result from reversing the inequality signs in both inequalities.

QUESTION 15

Choice B is correct. Squaring both sides of the given equation yields
x + 2 = x 2. Subtracting x and 2 from both sides of x + 2 = x 2
yields x 2 − x − 2 = 0. Factoring the left-hand side of this equation yields(x − 2)(x + 1) = 0. Applying the zero product property, the solutions
to (x − 2)(x + 1) = 0 are x − 2 = 0, or x = 2 and x + 1 = 0, or x = −1.
Substituting x = 2 in the given equation gives ​, which isfalse because ​by the definition of a principal square root.
So, x = 2 isn’t a solution. Substituting x = −1 into the given equation
gives ​
, which is true because −(−1) = 1. So x = −1 is the
only solution.
Choices A and C are incorrect. The square root symbol represents
theprincipal, or nonnegative, square root. Therefore, in the equation ​_√x + 2 = −x, the value of −x must be zero or positive. If x = 2, then−x = −2, which is negative, so 2 can’t be in the set of solutions.
Choice D is incorrect and may result from incorrectly reasoning that−x always has a negative value and therefore can’t be equal to a valueof a principal square root, which cannot be negative.
538

Answer Explanations | SAT Practice Test #9

QUESTION 16

The correct answer is 360. The volume of a right rectangular prismis calculated by multiplying its dimensions: length, width, and height.
Multiplying the values given for these dimensions yields a volume of(4)(9)(10) = 360 cubic centimeters.

QUESTION 17

The correct answer is 2. The left-hand side of the given equation contains
a common factor of 2 and can be rewritten as 2(2x + 1). Dividing both sidesof this equation by 2 yields 2x + 1 = 2. Therefore, the value of 2x + 1 is 2.
Alternate approach: Subtracting 2 from both sides of the given equation
1
yields 4x = 2. Dividing both sides of this equation by 4 yields x = — ​2
1
1
Substituting ​  — ​ for x in the expression 2x + 1 yields 2 ​  — ​  + 1 = 2.
2
2

( )

QUESTION 18

The correct answer is 8. The graph shows that the maximum value off(x) is 2. Since g(x) = f(x) + 6, the graph of g is the graph of f shifted up
by 6 units. Therefore, the maximum value of g(x) is 2 + 6 = 8.

QUESTION 19

The correct answer is ​  ​
.75. By definition of the sine ratio, since
PQ
4
4 _ —
PQ = 4n, then PR = 5n, where n is asin R = —5 ​, ​  PR = 5 ​positive constant. Then QR = kn, where k is another positive constant.
Applying the Pythagorean theorem, the following relationship holds:(kn)2 + (4n)2 = (5n)2, or k 2n2 + 16n2 = 25n2. Subtracting 16n2 from bothsides of this equation yields k 2n2 = 9n2. Taking the square root of bothsides of k 2n2 = 9n2 yields kn = 3n. It follows that k = 3. Therefore, if
PQ = 4n and PR = 5n, then QR = 3n, and by definition of the tangent ratio,
3n
3/4 or .75 may be entered as the correct answer.
tan P = — ​, or ​  ​
4n

QUESTION 20

The correct answer is 2.5. The graph of the linear function f passes
through the points (0, 3) and (1, 1). The slope of the graph of thefunction f is therefore ​ . It’s given that the graph of the linear
function g is perpendicular to the graph of the function f. Therefore, theslope of the graph of the function g is the negative reciprocal of −2, which111​   ​ g(x) = —x + b,
is − — ​ = —−2 2
2where b is a constant. Since it’s given that the graph of the function gpasses through the point (1, 3), the value of b can be found using the51equation 3 = — ​  (1) + b. Solving this equation for b yields b = — ​22
51equation that defines the function g is g(x) = —x + — ​. Finding the value of
2
2
5
5
1
g(0) by substituting 0 for x into this equation yields g(0) = — ​  (0) + —​   ​, or —​   ​.
2
2
2
Either 2.5 or 5/2 may be entered as the correct answer.
539

PART 4 | Eight Official Practice Tests with Answer Explanations

Section 4: Math Test – Calculator
QUESTION 1

Choice B is correct. Subtracting 3 from both sides of the equation
yields 3x = 24. Dividing both sides of this equation by 3 yields x = 8.
Choice A is incorrect and may result from finding a common factor
among the three given terms instead of finding x. Choice C is incorrect
and may result from incorrectly adding 3 to, instead of subtracting 3
from, the right-hand side of the equation. Choice D is incorrect. This isthe value of 3x + 3, not the value of x.

QUESTION 2

Choice D is correct. Since 1 cubit is equivalent to 7 palms, 140 cubits
are equivalent to 140(7) palms, or 980 palms.
Choice A is incorrect and may result from dividing 7 by 140. Choice B
is incorrect and may result from dividing 140 by 7. Choice C isincorrect. This is the length of the Great Sphinx statue in cubits,
not palms.

QUESTION 3

Choice B is correct. Multiplying both sides of the given equation by
5 yields 2n = 50. Substituting 50 for 2n in the expression 2n − 1 yields
50 − 1 = 49.
Alternate approach: Dividing both sides of 2n = 50 by 2 yields n = 25.
Evaluating the expression 2n − 1 for n = 25 yields 2(25) − 1 = 49.
Choice A is incorrect and may result from finding the value of n − 1
instead of 2n − 1. Choice C is incorrect and may result from finding thevalue of 2n instead of 2n − 1. Choice D is incorrect and may result fromfinding the value of 4n − 1 instead of 2n − 1.

QUESTION 4

Choice A is correct. The square root symbol represents the principal,
or nonnegative, square root. Therefore, the equation ​ ​is only true
for values of x greater than or equal to 0. Thus, −4 isn’t a solution to
the given equation.
Choices B, C, and D are incorrect because these values of x are
solutions to the equation ​ ​. Choosing one of these as a valueof x that isn’t a solution may result from incorrectly using therules of exponents or incorrectly evaluating these values in thegiven equation.

540

Answer Explanations | SAT Practice Test #9

QUESTION 5

Choice D is correct. The x-axis of the graph represents the time, in
minutes, after the coffee was removed from the heat source, and they-axis of the graph represents the temperature, in degrees Fahrenheit,of the coffee. The coffee was first removed from the heat source
when x = 0. The graph shows that when x = 0, the y-value wasa little less than 200°F. Of the answer choices given, 195 is thebest approximation.
Choice A is incorrect and may result from finding the temperature after
140 minutes. Choice B is incorrect and may result from finding thetemperature after 50 minutes. Choice C is incorrect and may result fromfinding the temperature after 10 minutes.

QUESTION 6

Choice A is correct. The average rate of change in temperature of
the coffee in degrees Fahrenheit per minute is calculated by dividing
the difference between two recorded temperatures by the number ofminutes in the corresponding interval of time. Since the time intervals
given are all 10 minutes, the average rate of change is greatest for the
points with the greatest difference in temperature. Of the choices, thegreatest difference in temperature occurs between 0 and 10 minutes.
Choices B, C, and D are incorrect and may result from misinterpretingthe average rate of change from the graph.

QUESTION 7

Choice C is correct. It’s given that x = 100; therefore, substituting 100
for x in triangle ABC gives two known angle measures for this triangle.
The sum of the measures of the interior angles of any triangle equals
180°. Subtracting the two known angle measures of triangle ABC from180° gives the third angle measure: 180° − 100° − 20° = 60°. This is
the measure of angle BCA. Since vertical angles are congruent, themeasure of angle DCE is also 60°. Subtracting the two known angle
measures of triangle CDE from 180° gives the third angle measure:180° − 60° − 40° = 80°. Therefore, the value of y is 80.
Choice A is incorrect and may result from a calculation error. Choice B
is incorrect and may result from classifying angle CDE as a right angle.
Choice D is incorrect and may result from finding the measure of angle
BCA or DCE instead of the measure of angle CDE.

QUESTION 8

Choice A is correct. The cost of each additional mile traveled isrepresented by the slope of the given line. The slope of the line can becalculated by identifying two points on the line and then calculating theratio of the change in y to the change in x between the two points. Using
the points (1, 5) and (2, 7), the slope is equal to ​  ​, or 2. Therefore,
the cost for each additional mile traveled of the cab ride is $2.00.
541

PART 4 | Eight Official Practice Tests with Answer Explanations

Choice B is incorrect and may result from calculating the slope of theline that passes through the points (5, 13) and (0, 0). However, (0, 0)
does not lie on the line shown. Choice C is incorrect. This is they-coordinate of the y-intercept of the graph and represents the flat fee fora cab ride before the charge for any miles traveled is added. Choice D
is incorrect. This value represents the total cost of a 1-mile cab ride.

QUESTION 9

Choice D is correct. The total number of gas station customers on
Tuesday was 135. The table shows that the number of customers who
did not purchase gasoline was 50. Finding the ratio of the numberof customers who did not purchase gasoline to the total number ofcustomers gives the probability that a customer selected at random onthat day did not purchase gasoline, which is ​  ​.
Choice A is incorrect and may result from finding the probability that acustomer did not purchase a beverage, given that the customer did notpurchase gasoline. Choice B is incorrect and may result from finding
the probability that a customer did not purchase gasoline, given thatthe customer did not purchase a beverage. Choice C is incorrect andmay result from finding the probability that a customer did purchase abeverage, given that the customer did not purchase gasoline.

QUESTION 10

Choice D is correct. It is given that the number of students surveyed
was 336. Finding ​  ​of 336 yields ​​   ​ , the number offreshmen, and finding ​  ​of 336 yields ​​   ​ , the number ofsophomores. Subtracting these numbers from the total number of
selected students results in 336 − 84 − 112 = 140, the number of juniors
and seniors combined. Finding half of this total yields ​​   ​ ,
the number of juniors. Subtracting this number from the number of juniors
and seniors combined yields 140 − 70 = 70, the number of seniors.
Choices A and C are incorrect and may result from calculation errors.
Choice B is incorrect. This is the total number of juniors and seniors.

QUESTION 11

Choice A is correct. It’s given that the ratio of the heights of Plant A
to Plant B is 20 to 12 and that the height of Plant C is 54 centimeters.
 ​ ​   ​can be used
Let x be the height of Plant D. The proportion ​ to solve for the value of x. Multiplying both sides of this equation byx yields ​  and then multiplying both sides of this equation by
12 yields 20x = 648. Dividing both sides of this equation by 20 yields
x = 32.4 centimeters.

542

Answer Explanations | SAT Practice Test #9

Choice B is incorrect and may result from a calculation error. Choice C
is incorrect and may result from finding the difference in heights
between Plant A and Plant B and then adding that to the height ofPlant C. Choice D is incorrect and may result from using the ratio 12 to
20 rather than 20 to 12.

QUESTION 12

Choice D is correct. It’s given that 1 kilometer is approximately
equivalent to 0.6214 miles. Let x be the number of kilometers equivalent ​ ​  ​can be used
to 3.1 miles. The proportion ​ to solve for the value of x. Multiplying both sides of this equation by
3.1
3.1 yields ​  —  ​ = x, or x ≈ 4.99. This is approximately 5 kilometers.
0.6214
Choice A is incorrect and may result from misidentifying the ratio of
kilometers to miles as miles to kilometers. Choice B is incorrect andmay result from calculation errors. Choice C is incorrect and may result
from calculation and rounding errors.

QUESTION 13

Choice C is correct. Let a equal the number of 120-pound packages,
and let b equal the number of 100-pound packages. It’s given thatthe total weight of the packages can be at most 1,100 pounds:
the inequality 120a + 100b ≤ 1,100 represents this situation. It’s also
given that the helicopter must carry at least 10 packages: the inequality
a + b ≥ 10 represents this situation. Values of a and b that satisfy
these two inequalities represent the allowable numbers of 120-pound
packages and 100-pound packages the helicopter can transport.
To maximize the number of 120-pound packages, a, in the helicopter,the number of 100-pound packages, b, in the helicopter needs to beminimized. Expressing b in terms of a in the second inequality yieldsb ≥ 10 − a, so the minimum value of b is equal to 10 − a. Substituting
10 − a for b in the first inequality results in 120a + 100(10 − a) ≤ 1,100.
Using the distributive property to rewrite this inequality yields
120a + 1,000 − 100a ≤ 1,100, or 20a + 1,000 ≤ 1,100. Subtracting 1,000
from both sides of this inequality yields 20a ≤ 100. Dividing both sidesof this inequality by 20 results in a ≤ 5. This means that the maximum
number of 120-pound packages that the helicopter can carry per trip is 5.
Choices A, B, and D are incorrect and may result from incorrectly
creating or solving the system of inequalities.

QUESTION 14

Choice B is correct. The difference between the machine’s starting
value and its value after 10 years can be found by subtracting $30,000
from $120,000: 120,000 − 30,000 = 90,000. It’s given that the value ofthe machine depreciates by the same amount each year for 10 years.
Dividing $90,000 by 10 gives $9,000, which is the amount by which
the value depreciates each year. Therefore, over a period of t years,
543

PART 4 | Eight Official Practice Tests with Answer Explanations

the value of the machine depreciates by a total of 9,000t dollars.
The value v of the machine, in dollars, t years after it was purchasedis the starting value minus the amount of depreciation after t years, orv = 120,000 − 9,000t.
Choice A is incorrect and may result from using the value of themachine after 10 years as the machine’s starting value. Choice C
is incorrect. This equation shows the amount the machine’s valuechanges each year being added to, rather than subtracted from, thestarting value. Choice D is incorrect and may result from multiplying
the machine’s value after 10 years by t instead of multiplying theamount the machine depreciates each year by t.

QUESTION 15

Choice D is correct. The slope-intercept form of a linear equation
is y = ax + b, where a is the slope of the graph of the equation and b
is the y-coordinate of the y-intercept of the graph. Two ordered pairs(x1, y1) and (x2, y2) can be used to compute the slope of the line with they2 − y1
formula a = —x2 − x1 ​. Substituting t he two ordered pairs (2, 4) and (0, 1)
4−1
into this formula gives a = _ ​, which simplifies to ​  ​. Substituting
2−0
this value for a in the slope-intercept form of the equation yields
3
y = — ​  x + b. Substituting values from the ordered pair (0, 1) into this23equation yields 1 = — ​  (0) + b, so b = 1. Substituting this value for b in23
the slope-intercept equation yields y = — ​  x + 1.
2
Choice A is incorrect. This may result from misinterpreting the change
in x-values as the slope and misinterpreting the change in y-values as
the y-coordinate of the y-intercept of the graph. Choice B is incorrect
and may result from using the x- and y-values of one of the given
points as the slope and y-coordinate of the y-intercept, respectively.
Choice C is incorrect. This equation has the correct slope but theincorrect y-coordinate of the y-intercept.

QUESTION 16

Choice B is correct. Multiplying the binomials in the given expression
results in 4ax 2 + 4ax − 4x − 4 − x 2 + 4. Combining like terms yields
4ax 2 + 4ax − 4 −x 2. Grouping by powers of x and factoring out theirgreatest common factors yields (4a − 1)x 2 + (4a − 4)x. It’s given that
this expression is equivalent to bx, so (4a − 1)x 2 + (4a − 4)x = bx. Since
the right-hand side of the equation has no x 2 term, the coefficient of
the x 2 term on the left-hand side must be 0. This gives 4a − 1 = 0 and
4a − 4 = b. Since 4a − 1 = 0, 4a = 1. Substituting the value of 4a into thesecond equation gives 1 − 4 = b, so b = −3.
Choices A, C, and D are incorrect and may result from a calculation error.

544

Answer Explanations | SAT Practice Test #9

QUESTION 17

Choice C is correct. Multiplying both sides of 2w + 4t = 14 by 2 yields
4w + 8t = 28. Subtracting the second given equation from 4w + 8t = 28
yields (4w − 4w) + (8t − 5t) = (28 − 25) or 3t = 3. Dividing both sidesof this equation by 3 yields t = 1. Substituting 1 for t in the equation
2w + 4t = 14 yields 2w + 4(1) = 14, or 2w + 4 = 14. Subtracting 4 fromboth sides of this equation yields 2w = 10, and dividing both sides ofthis equation by 2 yields w = 5. Substituting 5 for w and 1 for t in theexpression 2w + 3t yields 2(5) + 3(1) = 13.
Choices A, B, and D are incorrect and may result from incorrectly
calculating the values of w and t, or from correctly calculating thevalues of w and t but finding the value of an expression other than
2w + 3t. For instance, choice A is the value of w + t, choice B is thevalue of 2w, and choice D is the value of 2t + 3w.

QUESTION 18

Choice B is correct. It’s given that each serving of Crunchy Graincereal provides 5% of an adult’s daily allowance of potassium, so
x servings would provide x times 5%. The percentage of an adult’s
daily allowance of potassium, p, is 5 times the number of servings, x.
Therefore, the percentage of an adult’s daily allowance of potassium
can be expressed as p = 5x.
Choices A, C, and D are incorrect and may result from incorrectly
converting 5% to its decimal equivalent, which isn’t necessary since
p is expressed as a percentage. Additionally, choices C and D areincorrect because the context should be represented by a linear
relationship, not by an exponential relationship.

QUESTION 19

Choice B is correct. It’s given that a ​  ​

cereal provides 210 calories. The total number of calories per cup can
3
be found by dividing 210 by ​  ​
210 ÷ — = 280 calories per
4cup. Let c be the number of cups of Crunchy Grain cereal and s be thenumber of cups of Super Grain cereal. The expression 280c represents
the number of calories in c cups of Crunchy Grain cereal, and 240s
represents the number of calories in s cups of Super Grain cereal.
The equation 280c + 240s = 270 gives the total number of calories in
one cup of the mixture. Since c + s = 1 cup, c = 1 − s. Substituting 1 − sfor c in the equation 280c + 240s = 270 yields 280(1 − s) + 240s = 270,
or 280 − 280s + 240s = 270. Simplifying this equation yields
280 − 40s = 270. Subtracting 280 from both sides results in −40s = −10.
1
Dividing both sides of the equation by −40 results in s = — ​4
1is ​  — ​cup of Super Grain cereal in one cup of the mixture.
4
Choices A, C, and D are incorrect and may result from incorrectly
creating or solving the system of equations.
545

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 20

Choice A is correct. There are 0 calories in 0 servings of Crunchy
Grain cereal so the line must begin at the point (0, 0). Point (0, 0) is
the origin, labeled O. Additionally, each serving increases the calories
by 250. Therefore, the number of calories increases as the numberof servings increases, so the line must have a positive slope. Of the
choices, only choice A shows a graph with a line that begins at theorigin and has a positive slope.
Choices B, C, and D are incorrect. These graphs don’t show a line thatpasses through the origin. Additionally, choices C and D may result
from misidentifying the slope of the graph.

QUESTION 21

Choice D is correct. Since the function h is exponential, it can be
written as h(x) = abx, where a is the y-coordinate of the y-intercept
and b is the growth rate. Since it’s given that the y-coordinate of they-intercept is d, the exponential function can be written as h(x) = dbx.
These conditions are only met by the equation in choice D.
Choice A is incorrect. For this function, the value of h(x) when x = 0
is −3, not d. Choice B is incorrect. This function is a linear function,
not an exponential function. Choice C is incorrect. This function is apolynomial function, not an exponential function.

QUESTION 22

Choice B is correct. The median weight is found by ordering thehorses’ weights from least to greatest and then determining the middle
value from this list of weights. Decreasing the value for the horsewith the lowest weight doesn’t affect the median since it’s still thelowest value.
Choice A is incorrect. The mean is calculated by finding the sum of all
the weights of the horses and then dividing by the number of horses.
Decreasing one of the weights would decrease the sum and therefore
decrease the mean. Choice C is incorrect. Range is the difference
between the highest and lowest weights, so decreasing the lowest
weight would increase the range. Choice D is incorrect. Standard
deviation is calculated based on the mean weight of the horses.
Decreasing one of the weights decreases the mean and therefore would
affect the standard deviation.

QUESTION 23

Choice B is correct. In order for the poll results from a sample ofa population to represent the entire population, the sample must
be representative of the population. A sample that is randomly
selected from a population is more likely than a sample of the typedescribed to represent the population. In this case, the people who
responded were people with access to cable television and websites,546

Answer Explanations | SAT Practice Test #9

which aren’t accessible to the entire population. Moreover, the people
who responded also chose to watch the show and respond to thepoll. The people who made these choices aren’t representative of theentire population of the United States because they were not a random
sample of the population of the United States.
Choices A, C, and D are incorrect because they present reasons
unrelated to whether the sample is representative of the population of
the United States.

QUESTION 24

Choice C is correct. Substituting x + a for x in f(x) = 5x 2 − 3 yieldsf(x + a) = 5(x + a)2 − 3. Expanding the expression 5(x + a)2 by multiplication
yields 5x 2 + 10ax +5a2, and thus f(x + a) = 5x 2 + 10ax + 5a2 − 3. Setting
the expression on the right-hand side of this equation equal to thegiven expression for f(x + a) yields 5x 2 + 30x + 42 = 5x 2 + 10ax + 5a2 − 3.
Because this equality must be true for all values of x, the coefficients ofeach power of x are equal. Setting the coefficients of x equal to each othergives 10a = 30. Dividing each side of this equation by 10 yields a = 3.
Choices A, B, and D are incorrect and may result from a calculation error.

QUESTION 25

Choice C is correct. The sine of an angle is equal to the cosine of
the angle’s complement. This relationship can be expressed by theequation sin x° = cos (90° − x°). Therefore, if sin x° = a, thencos (90° − x°) must also be equal to a.
Choices A and B are incorrect and may result from misunderstanding
the relationship between the sine and cosine of complementary angles.
Choice D is incorrect and may result from misinterpreting sin (x 2)° as
sin2 (x)°.

QUESTION 26

Choice D is correct. The positive x-intercept of the graph of y = h(x)is a point (x, y) for which y = 0. Since y = h(x) models the height above
the ground, in feet, of the projectile, a y-value of 0 must correspondto the height of the projectile when it is 0 feet above ground or, inother words, when the projectile is on the ground. Since x represents
the time since the projectile was launched, it follows that the positivex-intercept, (x, 0), represents the time at which the projectile hits
the ground.
Choice A is incorrect and may result from misidentifying the y-intercept
as a positive x-intercept. Choice B is incorrect and may result frommisidentifying the y-value of the vertex of the graph of the function as
an x-intercept. Choice C is incorrect and may result from misidentifying
the x-value of the vertex of the graph of the function as an x-intercept.

547

PART 4 | Eight Official Practice Tests with Answer Explanations

QUESTION 27

Choice A is correct. Since (a, 0) and (b, 0) are the only two points
where the graph of f crosses the x-axis, it must be true that f(a) = 0
and f(b) = 0 and that f(x) is not equal to 0 for any other value of x. Of
the given choices, choice A is the only function for which this is true.
If f(x) = (x − a)(x − b), then f(a) = (a − a)(a − b), which can be rewritten
as f(a) = 0(a − b), or f(a) = 0. Also, f(b) = (b − a)(b − b), which can be
rewritten as f(b) = (b − a)(0), or f(b) = 0. Furthermore, if f(x) = (x − a)(x − b)is equal to 0, then it follows that either x − a = 0 or x − b = 0. Solving
each of these equations by adding a to both sides of the first equation
and adding b to both sides of the second equation yields x = a or x = b.
Therefore, the graph of f(x) = (x − a)(x − b) crosses the x-axis at exactly
two points, (a, 0) and (b, 0).
Choice B is incorrect because f(a) = (2a)(a + b), which can’t be 0
because it’s given that a and b are positive. Choice C is incorrect
because f(b) = (b − a)(2b); its graph could only be 0 if b = a, but it wouldcross the x-axis at only one point, since (a, 0) and (b, 0) would be thesame point. Choice D is incorrect because its graph crosses the x-axis
at (0, 0) as well as at (a, 0) and (b, 0).

QUESTION 28

Choice C is correct. Substituting 0 for x in the given equation yields
3(0)2 + 6(0) + 2 = 2. Therefore, the graph of the given equation passes
through the point (0, 2), which is the y-intercept of the graph. The
right-hand side of the given equation, y = 3x 2 + 6x + 2, displays theconstant 2, which directly corresponds to the y-coordinate of they-intercept of the graph of this equation in the xy-plane.
Choice A is incorrect. The y-coordinate of the vertex of the graphis −1, not 3, 6, or 2. Choice B is incorrect. The x-coordinates of thex-intercepts of the graph are at approximately −1.577 and −0.423, not 3,
6, or 2. Choice D is incorrect. The x-coordinate of the x-intercept of theline of symmetry is at −1, not 3, 6, or 2.

QUESTION 29

Choice A is correct. The given equation is in slope-intercept form,or y = mx + b, where m is the value of the slope of the line of best fit.
Therefore, the slope of the line of best fit is 0.096. From the definitionof slope, it follows that an increase of 1 in the x-value corresponds
to an increase of 0.096 in the y-value. Therefore, the line of best fit
predicts that for each year between 1940 and 2010, the minimum wage
will increase by 0.096 dollar per hour.
Choice B is incorrect and may result from using the y-coordinate of
the y-intercept as the average increase, instead of the slope. Choice C
is incorrect and may result from using the 10-year increments givenon the x-axis to incorrectly interpret the slope of the line of best fit.
Choice D is incorrect and may result from using the y-coordinate548

Answer Explanations | SAT Practice Test #9of the y-intercept as the average increase, instead of the slope, andfrom using the 10-year increments given on the x-axis to incorrectlyinterpret the slope of the line of best fit.

QUESTION 30

Choice D is correct. On the line of best fit, d increases fromapproximately 480 to 880 between t = 12 and t = 24. The slope of theline of best fit is the difference in d-values divided by the difference in
880 − 480 400
t-values, which gives ​  _ ​ = ​  —1224 − 12the equation of the line of best fit in slope-intercept form gives
d = 33t + b, where b is the y-coordinate of the y-intercept. This equation
is satisfied by all points on the line, so d = 480 when t = 12. Thus,
480 = 33(12) + b, which is equivalent to 480 = 396 + b. Subtracting 396
from both sides of this equation gives b = 84. Therefore, an equation
for the line of best fit could be d = 33t + 84.
Choice A is incorrect and may result from an error in calculating theslope and misidentifying the y-coordinate of the y-intercept of the graphas the value of d at t = 10 rather than the value of d at t = 0. Choice B isincorrect and may result from using the smallest value of t on the graphas the slope and misidentifying the y-coordinate of the y-interceptof the graph as the value of d at t = 10 rather than the value of d at
t = 0. Choice C is incorrect and may result from misidentifying they-coordinate of the y-intercept as the smallest value of d on the graph.

QUESTION 31

The correct answer is 6. Circles are symmetric with respect to any
given diameter through the center (h, k). One diameter of the circle
is perpendicular to the x-axis. Therefore, the value of h is the mean
20 + 4of the x-coordinates of the circle’s two x-intercepts: h = — = 12.
2
The radius of the circle is given as 10, so the point (h, k) must be a
distance of 10 units from any point on the circle. The equation of any
circle can be written as (x − h)2 + (y − k)2 = r 2, where (h, k) is the centerof the circle and r is the length of the radius of the circle. Substituting
12 for h and 10 for r into this equation gives (x − 12)2 + (y − k)2 = 102.
Substituting the x-coordinate and y-coordinate of a point on the circle,(4, 0), gives (4 − 12)2 + (0 − k)2 = 102, or 64 + k 2 = 100. Subtracting
64_
from both sides of this equation yields k 2 = 36. Therefore, k = ±√36 ​.
Since the graph shows the point (h, k) in the first quadrant, k must be
the positive square root of 36, so k = 6.

QUESTION 32

The correct answer is 2. It’s given that line ℓ is perpendicular to the22line with equation y = − — x. Since the equation y = − — x is written in3
3
2
slope-intercept form, the slope of the line is −​ — . The slope of line ℓ3
3
2
must be the negative reciprocal of −​ — , which is ​  — . It’s also given that
3
2
549

PART 4 | Eight Official Practice Tests with Answer Explanations

the y-coordinate of the y-intercept of line ℓ is −13, so the equation
3of line ℓ in slope-intercept form is y = — x − 13. If y = b when x = 10,23
b = — (10) − 13, which is equivalent to b = 15 − 13, or b = 2.
2

QUESTION 33

The correct answer is 8. In this group, ​  of the people whoare rhesus negative have blood type B. The total number ofpeople who are rhesus negative in the group is 7 + 2 + 1 + x, andthere are 2 people who are rhesus negative with blood type B.
1
2
Therefore, ​  —  ​ = ​  — ​  . Combining like terms on the left-hand(7 + 2 + 1 + x) 9 ​ ​ side of the equation yields ​equation by 9 yields ​, and multiplying both sides of thisequation by (10 + x) yields 18 = 10 + x. Subtracting 10 from both sidesof this equation yields 8 = x.

QUESTION 34

The correct answer is 9. The median number of goals scored is foundby ordering the number of goals scored from least to greatest and thendetermining the middle value in the list. If the number of goals scoredin each of the 29 games were listed in order from least to greatest, themedian would be the fifteenth number of goals. The graph shows there
were 8 games with 1 goal scored and 9 games with 2 goals scored.
Therefore, the fifteenth number, or the median number, of goals scoredmust be 2. According to the graph, the soccer team scored 2 goals in 9of the games played.

QUESTION 35

The correct answer is 15. It’s given that the deductions reduce theoriginal amount of taxes owed by $2,325.00. Since the deductions
reduce the original amount of taxes owed by d%, the equation
2,325
d​  —  ​ = ​  — can be used to find this percent decrease, d.
15,500 100
232,500
Multiplying both sides of this equation by 100 yields ​  — ​ = d, or
15,50015 = d. Thus, the tax deductions reduce the original amount of taxes
owed by 15%.

QUESTION 36

The correct answer is 1.5. It’s given that the system of linear
equations has no solutions. Therefore, the lines represented by the two
equations are parallel. Each of the equations can be written in slopeintercept form, or y = mx + b, where m is the slope of the line and b
3is the y-coordinate of the line’s y-intercept. Subtracting ​  — x from both
4
3
3
1
1
sides of ​  — x − — y = 12 yields −​ — y = − — x + 12. Dividing both sides of
4
4
2
2
550

Answer Explanations | SAT Practice Test #9

3

−​ —
12
1
4
x+—
this equation by −​ — yields y = —
1
1
2
−​ —
−​ —

3
y = — x − 24. Therefore, the2223
slope of the line represented by the first equation in the system is ​  — ​  .
2
The second equation in the system can be put into slope-intercept formby first subtracting ax from both sides of ax − by = 9, then dividing
9aboth sides of the equation by −b, which yields y = — ​x − — . Therefore,bbthe slope of the line represented by the second equation in the systemaa 3is ​  —  ​ ​  — = —bb 2
may be entered as the correct answer.

3/2 or 1.5

QUESTION 37

The correct answer is 1.3. The median number of tourists isfound by ordering the number of tourists from least to greatest anddetermining the middle value from this list. When the number oftourists in 2012 is ordered from least to greatest, the middle value, orthe fifth number, is 46.4 million. When the number of tourists in 2013is ordered from least to greatest, the middle value, or the fifth number,is 47.7 million. The difference between these two medians is47.7 million − 46.4 million = 1.3 million.

QUESTION 38

The correct answer is 3. Let y be the number of international tourist
arrivals in Russia in 2012, and let x be the number of these arrivals
in 2011. It’s given that y is 13.5% greater than x, or y = 1.135x. The
table gives that y = 24.7, so 24.7 = 1.135x. Dividing both sides of this24.7
equation by 1.135 yields ​  —  ​ = x, or x ≈ 21.8 million arrivals. The
1.135
difference in the number of tourist arrivals between these two years is
24.7 million − 21.8 million = 2.9 million. Therefore, the value of k is 3
when rounded to the nearest integer.

551

THIS PAGE IS INTENTIONALLY LEFT BLANK.