RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: If x is an odd negative integer and y is an even integer, which of the following statements must be true?
I. (3x - 2y) is odd
II. xy^2 is an even negative integer
III. (y^2 - x) is an odd negative integer
A.I only
B.II only
C.I and II
D.I and III
Answer: A.I only
Explanation: If x is an odd negative integer and y is an even integer, which of the following statements must be true?
I. (3x - 2y) is odd
3x - is always negative and odd
2y - can be 0, when y=0, or always even integer (positive or negative)
odd integer +/- even integer = always odd
I statement is always true
II. xy^2 is an even negative integer
y can be 0 => xy^2 = 0 (non-negative even) => II statement is not true
III. (y^2 - x) is an odd negative integer
y can be 0 => -x will be positive => III statement is not true
basing on above, only I statement will always be true
answer is A
Question: If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, what is the average marks of all the students?
A.53.23
B.54.68
C.51.33
D.50
Answer: B.54.68
Explanation: Explanation:
Average marks of batch 1 = 50
Students in batch 1 = 55
Total marks of batch 1 = 55 × 50
Average marks of batch2 = 55
Students in batch2 = 60
Total marks of batch2 = 60 × 55
Average marks of batch3 = 60
Students in batch3 = 45
Total marks of batch3 = 45 × 60
Total students = 55 + 60 + 45 = 160
Average marks of all the students
=(55×50)+(60×55)+(45×60)/160
=275+330+270/16
=875/16=54.68
Answer: Option B
Question: A room is 15m long, 4m broad and 3m height. Find the cost of white washing its four walls at 50p per m2 ?
A.33
B.57
C.55
D.99
Answer: B.57
Explanation: 2 *3(15 + 4) = 114
114 * 1/2 = Rs.57
Answer: B
Question: In a camp, there is a meal for 120 men or 200 children. If 170 children have taken the meal, how many men will be catered to with remaining meal?
A.30
B.20
C.18
D.57
Answer: C.18
Explanation: There is a meal for 200 children.
170 children have taken the meal.
Remaining meal is to be catered to 30 children.
Now, 200 children 120 men.
30 children = (120/200)x 30 = 18 men.
C
Question: A family had dinner in a restaurant and paid $30 for food. They also had to pay 9.5% sale tax and 10% for the tip. How much did they pay for the dinner?
A.$35.83
B.$35.84
C.$35.85
D.$35.86
Answer: C.$35.85
Explanation: SOLUTION
They paid for food, sales tax and tip, hence
total paid = $30 + 9.5% * 30 + 10% * 30 = $35.85
Answer C
Question: Two coins are tossed, find the probability that two Tails are obtained
A.1/3
B.1/4
C.1/5
D.1/7
Answer: B.1/4
Explanation: The sample space S is given by.
S = {(H,T),(H,H),(T,H),(T,T)}
Let E be the event "two heads are obtained".
E = {(T,T)}
P(E) = n(E) / n(S) = 1/4
B
Question: Tom and Linda stand at point A. Linda begins to walk in a straight line away from Tom at a constant rate of 2 miles per hour. One hour later, Tom begins to jog in a straight line in the exact opposite direction at a constant rate of 7 miles per hour. If both Tom and Linda travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes Tom to cover half of the distance that Linda has covered and the amount of time it takes Tom to cover twice the distance that Linda has covered?
A.60
B.56
C.84
D.90
Answer: B.56
Explanation: B is the answer....
D = TS where D=distance, T=Time and S=Speed
To travel half distance, (2+2T) = 7T ==> T = 2/5 ==> 24 minutes
To travel double distance, 2(2+2T) = 7T ==> 2 ==>80 minutes
Difference, 56 minutes
B
Question: The average runs scored by a batsman in 20 matches is 40. In the next 10 matches the batsman scored an average of 13 runs. Find his average in all the 30 matches?
A.31
B.67
C.29
D.97
Answer: A.31
Explanation: Total score of the batsman in 20 matches = 800.
Total score of the batsman in the next 10 matches = 130.
Total score of the batsman in the 30 matches = 930.
Average score of the batsman = 930/30 = 31.
Answer: A
Question: A certain airline's fleet consisted of 110 type A planes at the beginning of 1980. At the end of each year, starting with 1980, the airline retired 3 of the TYPE A planes and acquired 4 new type B plans. How many years did it take before the number of type A planes left in the airline's fleet was less than 50 percent of the fleet?
A.15
B.16
C.17
D.18
Answer: B.16
Explanation: Let x be the number of years.
4x > 110 - 3x
7x > 110
x > 15 + 5/7
The answer is B.
Question: The circumferences of the wheels of a carriage are 6 3/14 dm and 8 1/18 dm. What is the least distance in which both wheels simultaneously complete an integral number of revolutions ? How often will the points of the two wheels which were lowest at the time of starting touch the ground together in 1 kilometre ?
A.47
B.24
C.45
D.34
Answer: C.45
Explanation: LCM of 6 3/14 dm and 8 1/18 dm =435/2=217 1/2 dm
and the required no. of revolutions = 2*10000/435= 45.9
The required answer =45 times
Answer is C
Question: A tour group of 25 people paid a total of $630 for entrance to a museum. If this price included a 10% sales tax, and all the tickets cost the same amount, what was the face value of each ticket price without the sales tax?
Choices
A.$22.68
B.$23.94
C.$24
D.$25.20
Answer: A.$22.68
Explanation: A.
Question: A rectangular swimming pool is 20 feet by 28 feet. A deck that has uniform width surrounds the pool. The total area of the pool and deck is 884 square feet. What is the width of the deck?
A.2 feet
B.2.5 feet
C.3 feet
D.4 feet
Answer: C.3 feet
Explanation: Assume the width of the deck = x
Area of pool and deck = (20 + 2x)*(28 + 2x) =884 {The deck is present at both ends of the length and the breadth, hence we need to add 2x}
(20 + 2x)*(28 + 2x) =884 can be written as
(10 + x)*(14 + x) = 221
140 + 24x + x^2 = 221
x^2 + 24x - 81 = 0
(x + 27)(x - 3) = 0
Hence x = -27 or 3. But a length cannot be negative
Hence width of the deck = x = 3
Correct option: C
Question: The probability that B can shoot a target two out of two times is 0.35. What is the probability that the target will be missed by B immediately after such two shots?
A.0.25
B.0.65
C.0.75
D.0.4
Answer: D.0.4
Explanation: Suppose there are total 'x' shots.
B shoots 2 out of 2 times. means out of x shots (x>2) B shots 2 out of 2 ----> B shots at least 2 out of x.
therefore, 2/x = 0.25 (given)
the target will be missed by B immediately after such two shots : this means he can shot just twice ...the third shot cannot happen which means he missed (x-2) shots.
thus, the probabilty of missing just after 2 shots is (x-2)/x.
(x-2)/x = 1 - 2/x
= 1 - 0.35
= 0.65
Answer : D
Question: When 2/9 of the votes on a certain resolution have been counted, 3/4 of those counted are in favor of the resolution. What fraction x of the remaining votes must be against the resolution so that the total count will result in a vote of 2 to 1 against the resolution?
A.11/14
B.13/18
C.4/7
D.3/7
Answer: A.11/14
Explanation: If we use variable for total votes there will be too many fractions to manipulate with, so pick some smart #: let set total # of votes is 18.
2/9 of the votes on a certain resolution have been counted--> 4 counted and 18-4=14 votes left to be counted;
3/4 of those counted are in favor of the resolution--> 3 in favor and 1 against;
Ratio of those who voted against to those who voted for to be 2 to 1 there should be total of 18*2/3=12 people who voted against, so in the remaining 14 votes there should be 12-1=11 people who voted against. Thus x=11/14 of the remaining votes must be against.
Answer: A.
Question: How many positive integers less than 250 are there such that they are multiples of 15 or multiples of 16?
A.28.
B.29.
C.30.
D.31.
Answer: C.30.
Explanation: 250/15 = 16 (plus remainder) so there are 16 multiples of 15
250/16 = 15 (plus remainder) so there are 15 multiples of 16
We need to subtract 1 because 15*16 is a multiple of both so it was counted twice.
The total is 16+15-1 = 30
The answer is C.
Question: A boy can reach a certain place in 18 hours. If he reduces his speed by 1/30th, he goes 3 km less in that time. Find his speed.
A.5 km/hr.
B.6 km/hr
C.8 km/hr
D.14 km/hr
Answer: A.5 km/hr.
Explanation: Explanation :
Solution: Let the speed be x km/hr. then,
18x - (18 * 29x/30) = 3
=> 3X/5= 3
=> x = 5 km/hr.
Answer : A
Question: There are 6 identical pens and 8 identical books. In how many different ways can a person select at least one object from this set?
A.14
B.28
C.45
D.62
Answer: D.62
Explanation: We can select from 0 to 6 pens and from 0 to 8 books.
Thus the total possible ways to select objects is 7*9 = 63
We must subtract 1 for the case with 0 pens and 0 books.
The answer is D.
Question: A boat takes 19 hours for travelling downstream fro poin A to point B and coming back to a point C midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B?
A.180 km
B.190 km
C.220 km
D.230 km
Answer: A.180 km
Explanation: Sol.
Speed downstream = (14 + 4) km/hr = 18 km/hr;
Speed upstream = (14 - 4) km/hr = 10 km/hr.
Let the distance between A and B be x km. Then,
x/18 + (x/2)/10 = 19 ⇔ x/18 + x/20 = 19 ⇒ x = 180 km.
Answer A
Question: If the cost price of 10 articles is same as the selling price of 25 articles. Find the gain or loss percentage?
A.30% Gain
B.30% Loss
C.40% Gain
D.60% Loss
Answer: D.60% Loss
Explanation: Explanation:
10 cp = 25 sp
Cost price CP = 25
Selling price SP = 10
Formula = (SP-CP)/CP * 100 = (10 - 25)/25 * 100 = 60 % Loss
Answer: Option D
Question: If 5 women or 8 girls can do a work in 84 days. In how many days can 10 women and 5 girls can do the same work ?
A.33
B.66
C.55
D.32
Answer: D.32
Explanation: Given that 5 women is equal to 8 girls to complete a work so, 10 women=16 girls. Therefore 10women +5girls=16girls+5girls=21girls. 8 girls can do a work in 84 days then 21 girls= (8*84/21)=32days. Therefore 10 women and 5 girls can a work in 32days
Answer: D
Question: If 1/12 of the passengers on a ship are from North America, 1/4 are Europeans, 1/9 are from Africa, 1/6 are from Asia and the remaining 42 people are citizens of other continents, then how many passengers are on board the ship?
A.96
B.100
C.104
D.108
Answer: D.108
Explanation: 1/12 + 1/4 + 1/9 + 1/6 = (3+9+4+6)/36 = 11/18
Let x be the number of passengers on the ship.
42 = (7/18)x
x = 108
The answer is D.
Question: A women purchased 3 towels @ Rs.100 each, 5 towels @ Rs.150 each and two towels at a certain rate which is now slipped off from his memory. But she remembers that the average price of the towels was Rs.160. Find the unknown rate of two towels?
A.A)400
B.B)450
C.C)500
D.D)550
Answer: D.D)550
Explanation: 10 * 160 = 1600
3 * 100 + 5 * 150 = 1050
1600 – 1050 = 550
D
Question: How many positive integers less than 100 are neither multiples of 2 or5.
A.a)30
B.b)31
C.c)40
D.d)33
Answer: C.c)40
Explanation: To answer this Q we require to know
1) multiples of 2 till 100 = 100/2 = 50
2) Multiples of 5 till 100 = 100/5 = 20
add the two 50+20=70 ; subtract common terms that are multiple of both 2 and 5..
LCM of 2 and 5 = 10
Multiples of 10 till 100 = 100/10 = 10
so total multiples of 2 and 5 = 70-10 = 6
ans = 100-60 = 40
C
Question: Divide Rs.32000 in the ratio 1:7?
A.12000, 20000
B.12000, 200098
C.4000, 28000
D.12000, 20006
Answer: C.4000, 28000
Explanation: 1/8 * 32000 = 4000
7/8 * 32000 = 28000
Answer: C
Question: If the same letters represent the same digit and different letters represent different digits, what digit does the letter A represent?
A.1
B.2
C.3
D.4
Answer: D.4
Explanation: Look at the digits in the ones place, there are 2 possible values for A + B + B:
A + B + B = A or A + B + B = 10 + A.
If A + B + B = A , B = 0. If A + B + B = 10 + A, B = 5.
Since B is a leading digit of BA, B cannot be a 0. B has to be a 5.
Look at the digits in the tens place, there are 2 possible values for 5 + A + A + 1:
5 + A + A + 1 = 10 + A or 5 + A + A + 1 = 20 + A
If 5 + A + A + 1 = 10 + A, A = 4. If 5 + A + A + 1 = 20 + A, A = 14. Since A is a single digit number, A has to be 4.
correct answer D
Question: Convert the following in a fraction: 0.75%
A.75/100
B.3/4
C.1/75
D.2/5
Answer: B.3/4
Explanation: 0.75 =75/100 = 3/4
Answer is B.
Question: A bowl was filled with 100 ounces of milk, and 0.0001 ounce of the milk evaporated each day during a 50-day period. What percent of the original amount of milk evaporated during this period?
A.A)0.005%
B.B)0.05%
C.C)5%
D.D)50%
Answer: A.A)0.005%
Explanation: Total amount of milk evaporated each day during a 50-day period = .0001 * 50
= .005
percent of the original amount of milk evaporated during this period = (.005/100) * 100%
= 0.005 %
Answer A
Question: Ashley and Vinie work on a sales staff with 8 other salespeople. If five members of the staff will be chosen at random to attend a sales workshop, what is the probability that both Ashley and Vinie will be chosen?
A.1/10
B.3/28
C.2/9
D.1/4
Answer: C.2/9
Explanation: I did slightly different and hence obviously ended up with the answer 2/9.
I assumed that because Ashley and Vinie have to be chosen, the remaining selection is 3 people from 8.
8C3/10C5= 2/9. Option C.
Question: AMS employs 8 professors on their staff. Their respective probability of remaining in employment for 10 years are 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9. The probability that after 10 years at least 7 of them still work in AMS is ?
A.0.19
B.1.22
C.0.1
D.0.04096
Answer: D.0.04096
Explanation: Asking atleast 6 of them continue ,
it has 3 cases.
1 all 8 professors continue.
2 7 professors continue and 1 professors discontinue.
1st case all 8 continue is = 2/10*3/10*4/10*5/10*6/10*7/10*/8/10*9/10=9factorial/10power8
=362880/100000000
=>0.00363.
2nd case any 7 professors continue, and 1out of 8 discontinue ,8C1 means 8 ways.
= 2/10*3/10.......8/10*1/10, (9/10 prodbability professor discontinue then 1/10)
in this way if we calculate for 8 possibilities then value is =>0.03733.
=0.00363+0.03733+0.1436=0.18456=0.04096
D
Question: If Rs. 782 be divided into three parts, proportional to 1/2:2/3:3/4, then the first part is?
A.426
B.526
C.207
D.204
Answer: D.204
Explanation: Given ratio
= 1/2:2/3:3/4 = 6:8:9
1st part = 782 * 6/23
= Rs. 204.
Answer:D
Question: Find out the wrong number in the given sequence of numbers.
1, 2, 6, 15, 31, 56, 91
A.22
B.91
C.37
D.28
Answer: B.91
Explanation: Explanation:
1, 1 + 12 = 2, 2 + 22 = 6, 6 + 32 = 15, 15 + 42 = 31, 31 + 52 = 56, 56 + 62 = 92
Last number of given series must be 92 not 91.
Answer: B) 91
Question: rahul played weel in this season.his current batting averagge is 46.if he score 78 runs in today match.his batting average will become 54.how many matches had he played in this season.
A.8
B.10
C.3
D.6
Answer: C.3
Explanation: 46x+78=54(x+1)
=>8x=24
=>x=3
ANSWER:C
Question: The simple interest on Rs. 34 for 8 months at the rate of 6 paise per rupeeper month is
A.16.32
B.16.9
C.12.25
D.13.21
Answer: A.16.32
Explanation: Sol.
S.I. = Rs. [34 * 6/100 * 8] = Rs. 16.32
Answer A
Question: A train running at the speed of 58 km/hr crosses a pole in 9 seconds. Find the length of the train?
A.145
B.272
C.278
D.277
Answer: A.145
Explanation: Speed = 58*(5/18) m/sec = 145/9 m/sec
Length of Train (Distance) = Speed * Time
(145/9) * 9
= 145 meter
Answer: A
Question: A rectangular grassy plot 110 m. by 65 m has a gravel path 2.5 m wide all round it on the inside. Find the cost of gravelling the path at 70 paise per sq. metre
A.s595
B.s780
C.s880
D.s480
Answer: A.s595
Explanation: area of the plot=110m*65m=7150sq.m
area of plot excluding gravel=105m*60m=6300sq.m
area of gravel =7150sq.m-6300sq.m =850sq.m
cost of building it = 850sq.m*70
= 59500p
in Rs =59500/100=Rs595
ANSWER:A
Question: The average of 10 numbers is calculated as 15. It is discovered later on that while calculating the average one number, namely 36 was wrongly read as 26. The correct average is :
A.12.4
B.14
C.16
D.18.6
Answer: C.16
Explanation: Explanation:
Sum of numbers = (10××15-26+36)=160
Correct average = 160/10=16
Correct Option: C
Question: A woman sells two articles for Rs.3600 each and he gains 30% on the first and loses 30% on the next. Find his total gain or loss?
A.11%
B.700%
C.430%
D.9%
Answer: D.9%
Explanation: D
(30*30)/100 = 9%loss
Question: A man sells an article at 15% loss. Had he sold it for Rs. 70/- more he could have gained 20%. What is the cost price of the article?
A.Rs.200/-
B.Rs.400/-
C.Rs.460/-
D.Rs.480/-
Answer: A.Rs.200/-
Explanation: Explanation:
Short cut method:
Loss =====> 15 %
Profit ====> 20 %
~
----------------
35 % ---------> Rs. 70/-
100 % --------> Rs. 200/-
Answer: Option A
Question: The sector of a circle has radius of 21 cm and central angle 180o. Find its perimeter?
A.91.5
B.92
C.108
D.94
Answer: C.108
Explanation: Perimeter of the sector = length of the arc + 2(radius)
= (135/360 * 2 * 22/7 * 21) + 2(21)
= 108 cm
Answer: Option C
Question: If 40% of a number exceeds 25% of it by 18, then find the number?
A.120
B.150
C.200
D.64
Answer: A.120
Explanation: Use the elimination method to find the correct option.
Of all the options only 120 fits
40% of 120 = 48
25% of 120 = 30
48 -30 = 18
Required number is 180.
ANSWER:A
Question: Ramu bought an old car for Rs. 42000. He spent Rs. 13000 on repairs and sold it for Rs. 64900. What is his profit percent?
A.22
B.77
C.18
D.77
Answer: C.18
Explanation: Total CP = Rs. 42000 + Rs. 13000 = Rs. 55000 and SP = Rs. 64900
Profit(%) = (64900 - 55000)/55000 * 100 = 18%
Answer: C
Question: If l / r is an integer, which of the following statements must be true?
A.both l and r are integers
B.r / l is an integer
C.r is an integer
D.l = nr where n is an integer
Answer: D.l = nr where n is an integer
Explanation: Let l = 1/4; r = 1/8 --> l/r = 2
l= nr where n is an integer --> 1/4 = 2*(1/8) --> Correct
Answer: D
Question: Amy, Max and Nim, each have a basket full of apples. The number of apples each have is in the ratio 7:8:9 respectively. what could be the product of the number of apples.
A.4032
B.5012
C.1033
D.4123
Answer: A.4032
Explanation: The ratio is in in the order of consecutive positive integers. Therefore, the product of the numbers will be divisible by both 2 and 3.
4032 -> even number, 4+0+3+2=6 ->divisible by 3.
Answer:A
Question: A bicyclist's wheel has a circumference of 4 meters. if the bicyclist covers 40 meters in 5 hours at a constant speed, how many rotations does the wheel make per hour at that speed?
A.2
B.3
C.4
D.5
Answer: A.2
Explanation: The bicyclist covers y meters in t hrs. So he covers y/t meters in one hour.
To cover y/t meters, the bicycle's wheel went round and round that is, multiple times, the wheel completed one circumference on the road. How many times did it complete one full rotation. Since the circumference is x, the number of times it completes the circumference is y/xt.
given : x=4; y=40 and t=5
hence y/xt =40/4*5=2
Answer (A)
Question: How many perfect squares less than 1000 end with the digit 6?
A.3
B.4
C.5
D.6
Answer: D.6
Explanation: 4:16
6:36
14:196
16:256
24:576
26:676
ANSWER:D
Question: 5 friends went to a restaurant and decided to pay the bill amount equally. But 4 of them could pay Rs. 50 each as a result 5th has to pay Rs. 40 extra than his share. Find the amount paid by him.
A.130
B.110
C.50
D.100
Answer: D.100
Explanation: Explanation:
Average amount paid by 4 persons = Rs. 50
Increase in average due to Rs. 40 paid extra by the 5th men = Rs. 40/4= Rs. 10
Therefore, Average expenditure of 6 friends = Rs. 50 + Rs. 10 = Rs. 60
Therefore, Amount paid by the 6th men = Rs. 60 + Rs. 40 = Rs. 100
Correct Option: D
Question: A glass was filled with 40 ounces of water, and 0.01 ounce of the water evaporated each day during a 20-day period. What percent of the original amount of water evaporated during this period?
A.0.005%
B.0.02%
C.0.5%
D.5%
Answer: C.0.5%
Explanation: We are given that 0.01 ounces of water evaporated EACH DAY. Furthermore, we know that this process happened over a 20-DAY PERIOD. To calculate the total amount of water that evaporated during this time frame we need to multiply 0.01 by 20. This gives us:
0.01 x 20 = 0.2 ounces
Finally, we are asked for “What percent” of the original amount of water evaporated during this period. To determine this percentage, we have to make sure we translate the expression correctly. We can translate it to:
(Amount Evaporated/Original Amount) x 100%
(0.2/40) x 100%
= 0.5%
Answer C
Question: If two resistors, A(R1) and B(R2) stand in parallel with each other in electrical wire, the total resistor appears as R1R2/(R1+R2). If three resistors, A(R1), B(R2), and C(2R2) stand in parallel in electrical wire, what is the ratio D of the resistors’ sum of A and C to the resistors’ sum of A and B?
A.2(R1+R2):(R1+2R2)
B.(R1+R2):(R1+2R2)
C.(2R1+R2):(R1+2R2)
D.2(R1+R2):(2R1+R2)
Answer: A.2(R1+R2):(R1+2R2)
Explanation: two resistors A (r1) and B (r2).
total or sum of two resistors appear as
r1r2/r1+r2. It is looks like inversion of sum of rates.
1/r1+1/r2= r1+r2/r1r2.
same way sum of A(r1) and c(2r2)=1/r1+1/2r2
=2r2+r1/r12r2.
inversion rate = r12r2/2r2+r1.
ratio D of sum of a and c/sum of a and b=2r2r1/2r2+r1*r1+r2/r1r2
=2(r1+r2)/2r2+r1.A
Question: The speed of a car increases by 2 kms after every one hour. If the distance travelling in the first one hour was 35 kms. what was the total distance travelled in 12 hours?
A.456 kms
B.482 kms
C.552 kms
D.556 kms
Answer: C.552 kms
Explanation: Explanation:
Total distance travelled in 12 hours =(35+37+39+.....upto 12 terms)
This is an A.P with first term, a=35, number of terms,
n= 12,d=2.
Required distance = 12/2[2 x 35+{12-1) x 2]
=6(70+23)
= 552 kms.
ANSWER IS C
Question: The dimensions of a field are 20 m by 5 m. A pit 10 m long, 4 m wide and 3 m deep is dug in one corner of the field and the earth removed has been evenly spread over the remaining area of the field. What will be the rise in the height of field as a result of this operation ?
A.1m
B.5m
C.4m
D.2m
Answer: D.2m
Explanation: The volume of the earth removed is 10*4*3 = 120 m^3.
The remaining area of the field is 20*5 - 10*4 = 60 m^2.
120 m^3 of the earth evenly spread over the area of 60 m^2 will rise the height by (height) = (volume)/(area) = 120/60 = 2 m.
Answer: D
Question: 79 laboratories raise the bacterium, the laboratory have 48 culture dishes on average, which has about 25,073 bacteria each. How many bacteria are there approximately?
A.10^7
B.10^9
C.10^8
D.10^10
Answer: C.10^8
Explanation: 79 laboratories raise the bacterium, the laboratory have 48 culture dishes on average, which has about 25,073 bacteria each. How many bacteria are there approximately?
A. 10^7
B. 10^8
C. 10^9
D. 10^10
E. 10^11
-> Due to approximately, 79=80, 48=50, 25,073=25,000 are derived, which makes (79)(48)(25,075)=(80)(50)(25,000)=10^8. The answer is C.
Question: Each shelf of a bookcase contained 11 books. If the librarian took out 32 books and rearranged the remaining books so that all shelves but the last one contained 7 books and that last shelf contained 3 books, how many shelves does the bookcase have?
A.5
B.6
C.7
D.8
Answer: C.7
Explanation: Let x be the number of shelves.
11x - 32 = 7(x-1) + 3
4x = 28
x = 7
The answer is C.
Question: Five kg of butter was bought by a shopkeeper for 300. One kg becomes unsaleable. He sells the remaining in such a way that on the whole he incurs a loss of 10%. At what price per kg was the butter sold?
A.67.5
B.52.5
C.60
D.72.5
Answer: A.67.5
Explanation: Let S.P. = x per kg
∴ S.P. of 4 kg = 4x
∴ 4x = 100−40/100×300
⇒ x = 270⁄4 = 67.50
Answer A
Question: A man can row upstream at 7kmph and downstream at 10kmph. Find man's rate in still water ?
A.8.5km/hr
B.6.7km/hr
C.5km/hr
D.1.5km/hr
Answer: A.8.5km/hr
Explanation: Rate in still water = 1/2 (10+7) = 8.5km/hr
Answer is A
Question: A man can row a boat at 20 kmph in still water. If the speed of the stream is 5 kmph, what is the time taken to row a distance of 60 km downstream?
A.12/5 hours
B.80/13 hours
C.30/73 hours
D.30/13 hours
Answer: A.12/5 hours
Explanation: Speed downstream = 20 + 5 = 25 kmph.
Time required to cover 60 km downstream
= d/s = 60/25
= 12/5 hours.
Answer:A