RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: A bar over a sequence of digits in a decimal indicates that the sequence repeats indefinitely. What is the value of (10^4 -10^2)(0.0019)?
A.25
B.20
C.21
D.18.81
Answer: D.18.81
Explanation: You get 10^2 (100-1) (.0019)
we know 19/10000 = .0019
10^2 (99) * (19/10000)
10^2 = 100 and 100^2 = 10000
Cancel out the 100 with the 10^2
Left with 99(19/100).
0.99*19 = 18.81
Answer : D
Question: Two assembly line inspectors, smithy and glen, inspect widgets as they come off the assembly line. If smithy inspects every fifth widget, starting with the fifth, and glen inspects every third, starting with the third, how many of the 98 widgets produced in the first hour of operation are not inspected by either inspector?
A.50
B.53
C.55
D.60
Answer: B.53
Explanation: Widgets inspected by smithy: ((95-5)/5)+1=18+1=19
Widgets inspected by glen: ((96-3)/3)+1 =31+1 =32
Widgets inspected by both: ((90-15)+1 =6
Total : 19+32 -6=45
hence, widgets not inspected: 98-45=53
Option B
Question: A booster pump can be used for filling as well as for emptying a tank. The capacity of the tank is 2400 . The emptying capacity of the tank is 10 per minute heigher than its filling capacity and the pump needs 8 minutes lesser to empty the tank than it needs to fill it. What is the filling capacity of the pump?
A.50 m^3/min
B.90 m^3/min
C.50 m^9/min
D.59 m^3/min
Answer: A.50 m^3/min
Explanation: Explanation:
Let the filling capacity of the pump be x /min.
Then, emptying capacity of the pump=(x+10) /min.
so,
Answer: A) 50 m^3/min
Question: The annual budget of a certain college is to be shown on a circle graph. If the size of each sector of the graph is to be proportional to the amount of the budget it represents, how many degrees of the circle should be used to represent an item that is 20 percent of the budget?
A. 15 °
B. 36 °
C. 54 °
D. 72 °
Answer: D. 72 °
Explanation: 100 percent = 360 degrees
20 percent = 360*20/100 = 72 degrees
Answer is D.
Question: Marts income is 50 percent more than Tims income and Tims income is 40 percent less than Juans income. What percentage of Juans income is Marts income
A.124%
B.b) 120 %
C.c) 96 %
D.d) 90 %
Answer: D.d) 90 %
Explanation: M = (150/100)T
T = (60/100)J
=> M = (90/100)J
Answer D.
Question: Joe’s average (arithmetic mean) test score across 4 equally weighted tests was 60. He was allowed to drop his lowest score. After doing so, his average test score improved to 65. What is the lowest test score that was dropped?
A.20
B.45
C.55
D.65
Answer: B.45
Explanation: The arithmetic mean of 4 equally weighted tests was 60. So what we can assume is that we have 4 test scores, each 60.
He dropped his lowest score and the avg went to 65. This means that the lowest score was not 60 and other three scores had given the lowest score 5 each to make it up to 60 too. When the lowest score was removed, the other 3 scores got their 5 back. So the lowest score was 3 *5 = 15 less than 60.
So the lowest score = 60 - 15 = 45
Answer (B)
Question: A batsman makes a score of 87 runs in the 17th inning and thus increases his avg by 3. Find his average after 17th inning.
A.12
B.39
C.43
D.52
Answer: B.39
Explanation: Let the average after 17th inning = x.
Then, average after 16th inning = (x - 3).
:. 16 (x - 3) + 87 = 17x or x = (87 - 48) = 39.
Ans: B
Question: Pipes A and B can fill a cistern in 8 and 24 minutes respectively. They are opened an alternate minutes. Find how many minutes, the cistern shall be full?
A.16
B.12
C.14
D.61
Answer: B.12
Explanation: 1/8 + 1/24
= 1/6
6 * 2
= 12
Answer:B
Question: A survey of employers found that during 1993 employment costs rose 3.5 percent, where employment costs consist of salary costs and fringe-benefit costs. If salary costs rose 3 percent and fringe-benefit costs rose 6.5 percent during 1993, then fringe-benefit costs represented what percent of employment costs at the beginning of 1993 ?
A. 16.5%
B. 14%
C. 35%
D. 55%
Answer: B. 14%
Explanation: The amount by which employment costs rose is equal to 0.035(salary costs + fringe benefit costs);
On the other hand the amount by which employment costs rose is equal to 0.03*salary costs + 0.065*fringe benefit costs;
So, 35(S+F) = 30S+65F --> S = 6F --> F/S = 1/6 --> F/(S+F) = 1/(1+6) = 1/7 = 0.14.
Answer: B.
Question: Mr. Das decided to walk down the escalator of a mall. He found that if he walks down 26 steps, he requires 30seconds to reach the bottom. However, if he steps down 34 stair she would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way insteps?
A.5
B.6
C.7
D.8
Answer: B.6
Explanation: here when he step down 26 steps he has 30 seconds for remaining steps.
if he step down 34 stairs he has only 18 sec.
30-18=12
12 secs for 8 steps..
18 secs for 12 steps.
12+34=46
so ans is 46..
ANSWER:B
Question: Find the fourth proportional to 2.4, 4.6 and 7.6?
A.14
B.14.657
C.15.56
D.14.56
Answer: D.14.56
Explanation: Explanation:
Formula = Fourth propotional = (b × c)/a
A = 2.4 , B = 4.6 and C = 7.6
(4.6 × 7.6)/2.4 = 14.56
Answer: Option D
Question: The sum of first five prime numbers is?
A.20
B.25
C.26
D.28
Answer: D.28
Explanation: Required sum = (2 + 3 + 5 + 7 + 11) = 28.
Note: 1 is not a prime number.
Definition: A prime number (or a prime) is a natural number that has exactly two distinct natural number divisors: 1 and itself
Option D
Question: Two identical machines have the ability to produce both nuts and bolts. However, it takes 1 second to produce a bolt but 2 seconds to produce a nut. What is the fastest the two machines, working together, can produce 1,400 nuts and 1,400 bolts?
A.1,250 seconds
B.1,500 seconds
C.1,750 seconds
D.2,100 seconds
Answer: D.2,100 seconds
Explanation: I used the Rate formula (R=\frac{1}{T})
Rate of 1st machine = Rate of making 1 bolt + Rate of making 1 nut = 1 + \frac{1}{2}
Rate of 1st machine = Rate of 2nd machine
After this I got lost.
Please can you help how to approach using algebra?
I wouldn't complicate:
1 machine needs 1,400*1 seconds to produce 1,400 bolts, so 2 need half of that, so 1,400/2 seconds.=700
1 machine needs 1,400*2 seconds to produce 1,400 nuts, so 2 need half of that, so 1,400*2/2 seconds.=1400
total = 2100 sec
D
Question: L.C.M of two prime numbers x and y (x>y) is 161. The value of 3y-x is :
A.-2
B.-1
C.1
D.2
Answer: A.-2
Explanation: Explanation:
H. C. F of two prime numbers is 1. Product of numbers = 1 x 161 = 161.
Let the numbers be a and b . Then , ab= 161.
Now, co-primes with product 161 are (1, 161) and (7, 23).
Since x and y are prime numbers and x >y , we have x=23 and y=7.
inline fn_jvn therefore 3y-x = (3 x 7)-23 = -2 . Answer: A
Question: A circular jogging track forms the edge of a circular lake that has a diameter of 2 miles. Johanna walked once around the track at the average speed of 1 miles per hour. If t represents the number of hours it took Johanna to walk completely around the lake, which of the following is a correct statement?
A.0.5< t < 0.75
B.1.75< t < 2.0
C.6.0 < t < 6.5
D.2.5 < t < 3.0
Answer: C.6.0 < t < 6.5
Explanation: D=2, and R=1
circumference thus is 2pi miles
we know that she walked 1mph
knowing the formula rt=D, we can deduce that t= D/r
D is 2pi miles and r is 1mph
t = 2pi/1
pi can be rewritten as 22/7
2*22/7 = 44/7 and multiply this by 1/1 = 44/7. This is greater than 6, but less than 6.5, therefore, 6<t<6.5. Answer choice C.
Question: A man cycling along the road noticed that every 12 minutes a bus overtakes him and every 4 minutes he meets an oncoming bus. If all buses and the cyclist move at a constant speed, what is the time interval between consecutive buses?
A.5 minutes
B.6 minutes
C.8 minutes
D.9 minutes
Answer: B.6 minutes
Explanation: Let's say the distance between the buses is d. We want to determine Interval=\frac{d}{b}, where b is the speed of bus.
Let the speed of cyclist be c.
Every 12 minutes a bus overtakes cyclist: \frac{d}{b-c}=12, d=12b-12c;
Every 4 minutes cyclist meets an oncoming bus: \frac{d}{b+c}=4, d=4b+4c;
d=12b-12c=4b+4c, --> b=2c, --> d=12b-6b=6b.
Interval=\frac{d}{b}=\frac{6b}{b}=6
Answer: B (6 minutes).
Question: P software has coding line 5% more than N, N software has coding line 1/3 more than M. M software has 90 lines of coding. find P lines.
A.106
B.107
C.126
D.109
Answer: C.126
Explanation: M s/w has 90 line of code
N s/w has = 90+90*1/3= 120 line of code
P s/w 5% more N' code 120+6=126
ANSWER:C
Question: In a locality, the prevailing price of a 700 square feet property last year was US Dollar 1000. The owner made some additions and the 900 square feet property is now fetching a price of US Dollar 1500. By approximately what percent did the ratio of price to size increase from the previous year's price?
A.12
B.14
C.17
D.21
Answer: C.17
Explanation: Initial price/area ratio = 1000/700 = 9000/6300
Revised mileage/weight ratio = 1500/900 = 10500/6300
Answer: C
Question: If 5 machines can produce 20 units in 10 hours, how long would it take 10 to produce 80 units?
A.63
B.20
C.42
D.65
Answer: B.20
Explanation: 5 machines would produce 80 units in 40 hours. Increasing the amount of machines by 2 would mean dividing 40 hours by 2.
40/2 = 20
Answer : B
Question: There is a square with sides of 9. What is the area of the biggest circle that can be cut out of this square?
A.72.83
B.63.62
C.81
D.254.47
Answer: B.63.62
Explanation: Area of a circle = area=Ï€r^2
Square is 9 wide, so circle's diameter would be 9, and radius would be 4.5
area=Ï€4.5^2 which is approximately 63.62
Answer is B
Question: There are 8 stations between Vijayawada and Chennai. How many second class tickets have to be printed, so that a passenger can travel from any station to any other station?
A.100
B.90
C.190
D.110
Answer: B.90
Explanation: The total number of stations = 10
From 10 stations we have to choose any two stations and the direction of travel (i.e.,Vijayawada to Chennai is different from Chennai to Vijayawada) in 10P2 ways.
10P2= 10 * 9 = 90
ANSWER: B
Question: In how many ways can the letters of the English alphabets be arranged so that there are seven letters between the letters A and B, and no letter is repeated?
A.24P7*2*18!
B.24P7*2*20!
C.18*24!
D.36*24!
Answer: A.24P7*2*18!
Explanation: first we can arrange 7 letter b/w in 24p7 way
then A and B can be arrenge in *2 way so total is 24p7*2
no consider this 9 letter as 1 number so remainin number can be arrange in
(26-9+1)!
so ans = 24p7*2*18!
ANSWER:A
Question: Which of the following CANNOT be a product of two distinct positive integers X and Y?
A.X
B.Y
C.3Y + 2X
D.Y - X
Answer: D.Y - X
Explanation: In these questions it is best to take an example as if something is true for all positive integers than it as to be true for the smallest and the easiest integers to work with
take X = 1 and Y = 2 and work with the options
XY = 2
A) X take X =2, Y = 1
B) Y take X = 1 Y = 2
C) 3Y + 2X Seems tricky, lets see other options and then come back to it.
D) Y - X take Y = 1 and X = 2 --> Y - X = -1 .. How the hell can product of two positive integers be negative ?? or less than each of them?
E) YX Always true
You don't even have to worry what C is !
ans D
Question: How many cubes of 10cm edge can be put in a cubical box of 1m edge
A.10
B.100
C.1000
D.10000
Answer: C.1000
Explanation: Explanation:
number of cubes=(100 x 100 x 100)/(10 x 10 x 10)=1000
Answer: C
Question: In what time a sum of money double itself at 5% per annum simple interest?
A.33 1/8%
B.20%
C.83 1/3%
D.33 4/3%
Answer: B.20%
Explanation: P = (P*5*R)/100
R = 20%
Answer:B
Question: 3 years before age of A was double than age of B.after 7 years the sum of their ages will 83.calculate the age of A.
A.24
B.21
C.40
D.45
Answer: D.45
Explanation: Let 3 years before age of B=x year and age of A=2x year
present age of B=(x+3) and present age of A=(2x+3)
after 7 years age of B=(x+10) year and age of A=(2x+10) year
(x+10)+(2x+10)=83,3x=63,x=21.
present age of A=(2x+3)=45 years
answer D
Question: A started a business with 4500 and another person B joined after some period with 3000. Determine this period after B joined the business if the profit at the end of the year is divided in the ratio 2 : 1
A.After 3 months
B.After 4 months
C.After 6 months
D.After 2 1⁄2 months
Answer: A.After 3 months
Explanation: Let B joined after x months.
Then, 4500 × 12 : 3000 (12 – x) = 2 : 1
Ratio of their investments
4500×12/3000(12−x)=2/1 ⇒ x = 3
Answer A
Question: A total of 525 players participated in a single tennis knock out tournament. What is the total number of matches played in the tournament? (Knockout means if a player loses, he is out of the tournament). No match ends in a tie.
A.511
B.512
C.256
D.524
Answer: D.524
Explanation: There are 525 players, only 1 person wins, 524 players lose. in order to lose, you must have lost a game.
524 games.
Ans- D
Question: A retail item is offered at a discount of x percent (where x > 10), with a 5% state sales tax assessed on the discounted purchase price. If the state sales tax were not assessed, what percent discount from the item’s original retail price, in terms of x, would result in the same final price?
A.x+5/1.05
B.x/1.05 +5
C.1.05x-5
D.x-5/1.05
Answer: C.1.05x-5
Explanation: Let y be the price of the item.
Final price after discount and sales tax = y * (1 - x/100) * 1.05
Let z be the percent discount which would result in the same final price.
Then,
y * (1 - x/100) * 1.05 = y * (1 - z/100)
=> 1.05 - 1.05x/100 = 1 - z/100
=> z/100 = 1.05x/100 - .05
=> z = 1.05x - 5
Hence ,option C is correct.
Question: A magician has five animals in his magic hat: 3 doves and 2 rabbits. If he pulls two animals out of the hat at random, what is the chance W that he will have a matched pair?
A.W=2/5
B.W=3/5
C.W=1/5
D.1/2
Answer: A.W=2/5
Explanation: P(both doves) + P(both rabbits) = p(matched pair)
(3/5)*(2/4) + (2/5)*(1/4) = 2/5
Hi How did you get the probability 2/4 and 1/4???
You have 3 doves and 2 rabbits i.e. a total of 5 animals.
The probability that you pick a dove on your first pick is 3/5 (since there are 3 doves)
The probability that you pick a dove on your second pick too is 2/4 (because now only 2 doves are left after we picked a dove in the first pick. ALso only 4 animals are left to choose from)
Similarly,
The probability that you pick a rabbit on your first pick is 2/5 (since there are 2 rabbits)
The probability that you pick a rabbit on your second pick too is 1/4 (because now only 1 rabbit is left after we picked a rabbit in the first pick. Also only 4 animals are left to choose from)
Probability of picking a matched pair = 3/5 * 2/4 + 2/5 * 1/4 = 2/5
Question: 0.0005521/0.0000110 x 15.05=?
A.7534
B.255.4
C.756.4
D.755.4
Answer: D.755.4
Explanation: Explanation :
? = 0.0005521/0.0000110 x 15.05 = 755.4
Answer : Option D
Question: A trader bought a car at 20% discount on its original price. He sold it at a 40% increase on the price he bought it. What percent of profit did he make on the original price?
A.18%
B.22%
C.12%
D.92%
Answer: C.12%
Explanation: Original price = 100
CP = 80
S = 80*(140/100) = 112
100 - 112 = 12%
Answer: C
Question: M is the sum of the reciprocals of the consecutive integers from 601 to 700, inclusive. Which of the following is true?
A.1/7 < M < 1/6
B.1/5 < M < 1/3
C.1/7 < M < 1/5
D.1/9 < M < 1/7
Answer: A.1/7 < M < 1/6
Explanation: M = 1/601 + 1/602 + 1/603 + ...... + 1/700
If we replace the first 99 terms by 1/700, then we get a sum = 100/700 = 1/7. Since the actual terms are larger than 1/700, the sum is larger than 1/7.
If we replace the all the 100 terms by 1/600, we get a sum = 100/600 = 1/6. Since the actual terms are smaller than 1/600, the sum is less than 1/6.
Therefore 1/7 < M < 1/6
Choice A
Question: 16.036 divided by 0.04 gives :
A.40.09
B.4.06
C.40.06
D.400.9
Answer: D.400.9
Explanation: = 16.036/0.04
= 1603.6/4
= 400.9
Answer is D.
Question: Donovan and Michael are racing around a circular 300-meter track. If Donovan runs each lap in 45 seconds and Michael runs each lap in 40 seconds, how many laps will Michael have to complete in order to pass Donovan, assuming they start at the same time?
A.6
B.9
C.8
D.7
Answer: B.9
Explanation: One way of approaching this question is by Relative speed method
1. Speed/ Rate of Donovan = Distance/ time => 300/45 =>60/9
2. Speed/ Rate of Michael = Distance/ time => 300/40 => 30/4
Relative Speed between them =30/4 - 60/9 => 270 -240/36 = 30/36 =5/6 (We subtract the Rates if moving in the same direction and add the rates if moving in the opposite direction)
In order to pass Donovan-
Distance to be covered = 300, Relative Rate = 5/6
Total Time taken by Micheal to surpass Donovan = Distance / rate => 300*6/5 => 1800/5 => 360
No. of laps taken by Michael = Total time / Michael's rate => 360/40 => 9
Hence correct answer is 9 Laps.
B
Question: A wheel rotates 10 times every minute and moves 40 cm during each rotation. How many metres does
the wheel move in one hour?
A.123 metre
B.240 metre
C.120 metre
D.1200 metre
Answer: B.240 metre
Explanation: Expl : Number of times wheel moves in 1 hour = 10 * 60 = 600
:. Distance moves = (600 *40) cm = 24000 cm
In metres = 240 metre
Answer: B
Question: The speed of a boat in still water is 50kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
A.70,30 kmph
B.80,40 kmph
C.10,40 kmph
D.80,80 kmph
Answer: A.70,30 kmph
Explanation: Speed downstream = 50 + 20
= 70 kmph
Speed upstream = 50 - 20
= 30 kmph
Answer: A
Question: A certain violet paint contains 30 percent blue pigment and 70 percent red pigment by weight. A certain green paint contains 50 percent blue pigment and 50 percent yellow pigment. When these paints are mixed to produce a brown paint, the brown paint contains 40 percent blue pigment. If the brown paint weighs 10 grams, then the red pigment contributes how many grams of that weight?
A.2.8
B.3.5
C.4.2
D.5
Answer: B.3.5
Explanation: 10 Grams of combined mixture and 40% blue pigment means that the mixtures were mixed 50% each.
Thus 5 grams a piece. Out of the 5 grams of the violet paint, 70% is red.
Therefore, 5*.7 = 3.5 Grams of red pigment
ANSWER:B
Question: Arun and Amit started walking from two different points 'A' and 'B' respectively.Arun walks 2 kms North and turns to the East and walks 3 kms and again turns to North walks 4 kms and finally turns to East and Walks 5kms to reach point 'C'. Similarly, Amit walks 2 kms North and turns to west and walks 3 kms and finally turns to North, walks 4 kms and meets Arun at point 'C'. What is the distance between Arun and Amit's starting points?
A.5 km
B.8 km
C.11 km
D.13 km
Answer: C.11 km
Explanation: Explanation:
Where A= Arun's starting point; B = Amit's starting point; C = The point where Arun and Amit meet
PQ + RC + ST = 3 + 5 + 3 = 11 kms.
ANSWER IS C
Question: Find the missing number in the given sequence : 1,2,3,5,?,13,21,?
A.8 & 34
B.7 & 34
C.9 & 34
D.7 & 35
Answer: A.8 & 34
Explanation: 1+2=3
2+3=5
3+5=8
5+8=13
8+13=21
13+21=34
ANSWER:A
Question: What is 7 1/4 - 4 2/3 divided by 7/8 - 3/4 ?
A.87/36
B.36/17
C.7/6
D.62/3
Answer: D.62/3
Explanation: 7 1/4 - 4 2/3 = 29/4 - 14/3 = (87 - 56 )/12 = 31/12
7/8 - 3/4 = (7-6)/8 = 1/8
So 31/12/1/8 = 31/12 * 8 = 62/3
Answer - D
Question: Set C consists of 19 elements. The average of set C is L. If a new element is added to the set and the average grows by K, what is the value of the new element?
A.a) L(1 + K / 5)
B.b) L * (K/100) - 20L
C.c) 20L(1+K/100)
D.d) 20(1+K/100)-19L
Answer: A.a) L(1 + K / 5)
Explanation: Let's assume the value of new element to bea. So converting the word problem into equation,
(19*L + a) / (19 + 1) = L + k ==> after solving the equation we will get a (value of newly added element) = L + 20K
But according to the answer options, problem writer wanted to conveyk% percent rise in average value.
If we consider this case than resulting equation will be,
(19*L + a) / ( 19+1 ) = L + (K/100)*L ==> 19L + a = 20 [ L + KL/100]
==> a= 20L + KL/5 -19L
==> a= L + KL/5 , which is equivalent to option [A]
Question: Xavier, Yvonne, and Zelda each try independently to solve a problem. If their individual probabilities for success are 1/6, 1/2 and 5/8, respectively, what is the probability that Xavier and Yvonne, but not Zelda, will solve the problem?
A.1/32
B.7/8
C.9/64
D.5/64
Answer: A.1/32
Explanation: P(Xavier will solve)=1/6
P(Yvonne will solve)=1/2
P(Zelda will NOT solve) = 1- 5/8 = 3/8.
Now, we need to multiply all this Ps to find an answer:
p= (1/6)*(1/2)*(3/8) = 1/32.
Ans. A.
Question: The bankers discount and the true discount of a sum at 15% per annum simple interest for the same time are Rs.120 and Rs.60 respectively. What is the sum and the time?
A.Sum = Rs.160 and Time = 6.6 years
B.Sum = Rs.120 and Time = 6.6 years
C.Sum = Rs.140 and Time = 6.6 years
D.Sum = Rs.200 and Time = 6 years
Answer: B.Sum = Rs.120 and Time = 6.6 years
Explanation: Explanation :
BD = Rs.120
TD = Rs.60
R = 15%
F = BD ×TD/(BD – TD)=120×60/(120–60)=120×60/60=Rs. 120
BD = Simple Interest on the face value of the bill for unexpired time =FTR/100
⇒120 = (120×T×15)/100
⇒1200 = 12 × T × 15 ⇒100 = 15 × T
⇒ T = 100/15 = 6.6 years Answer : Option B
Question: Anil can do a work in 15 days while Sunil can do it in 25 days. How long will they take if both work together?
A.9 3/6
B.9 3/4
C.9 3/8
D.5 3/2
Answer: C.9 3/8
Explanation: 1/15 + 1/25 = 8/75
75/8 = 9 3/8 days
Answer:C
Question: Average of first five multiples of 4 is
A.12
B.11
C.13
D.15
Answer: A.12
Explanation: Explanation:
Average=4(1+2+3+4+5)/5=12
Answer: Option A
Question: A card shop contains 5 birthday cards, 4 holiday cards, and 3 graduation cards. If three cards are purchased at random from the shop, what is the probability that the three cards will be graduation cards?
A.1/33
B.6/264
C.1/44
D.1/264
Answer: D.1/264
Explanation: It doesn't matter which type of card you choose, so:
Probability of choosing 1st card: 3/12
Probability of choosing 2nd card of the same type: 2/11
Probability of choosing 3rd card of the same type: 1/10
Multiply and you get 1/264
Answer D.
Question: A train crosses a platform of 180 m in 15 sec, same train crosses another platform of length 250 m in 20 sec. then find the length of the train?
A.30
B.887
C.167
D.197
Answer: A.30
Explanation: Length of the train be ‘X’
X + 180/15 = X + 250/20
20X + 3600 = 15X + 3750
5x=150
X = 30m
Answer: A
Question: Each night before he goes to bed, Jordan likes to pick out an outfit to wear the next day. He has 12 different shirts, 10 different pairs of jeans, and 5 pairs of sneakers. If an outfit consists of 1 shirt, 1 pair of jeans, and 1 pair of sneakers, how many different outfits does Jordan have?
A.30
B.90
C.600
D.480
Answer: C.600
Explanation: Total # of outfits = 12 * 10 *5 = 600
Answer - C
Question: A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If two marbles are picked at random, what is the probability that they are either blue or yellow?
A.2/28
B.2/27
C.2/21
D.2/89
Answer: C.2/21
Explanation: Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles. Probability that both marbles are blue = ³C₂/¹⁵C₂ = (3 * 2)/(15 * 14) = 1/35
Probability that both are yellow = ²C₂/¹⁵C₂ = (2 * 1)/(15 * 14) = 1/105
Probability that one blue and other is yellow = (³C₁ * ²C₁)/¹⁵C₂ = (2 * 3 * 2)/(15 * 14) = 2/35
Required probability = 1/35 + 1/105 + 2/35
= 3/35 + 1/105 = 1/35(3 + 1/3)
= 10/(3 * 35)
= 2/21
Answer: C
Question: A bag contains 10 green and 8 white balls. If two balls are drawn simultaneously, the probability that both are of the same colour is
A.8/15
B.21/44
C.3/5
D.11/15
Answer: B.21/44
Explanation: Drawing two balls of same color from ten green balls can be done in 10C₂ ways.
Similarly from eight white balls two can be drawn in ⁸C₂ ways.
P = 10C₂/¹⁵C₂ + ⁸C₂/¹⁵C₂ = 21/44
ANSWER:B