RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: Length of a rectangular plot is 24 mtr more than its breadth. If the cost of fencin gthe plot at 26.50 per meter is Rs. 5300, what is the length of the plot in mtr?
A.52 m
B.62 m
C.72 m
D.82 m
Answer: B.62 m
Explanation: Let breadth = x metres.
Then, length = (x + 24) metres.
Perimeter = 5300 m = 200 m.
26.50
2[(x + 24) + x] = 200
2x + 24 = 100
2x = 76
x = 38.
Hence, length = x + 24 = 62 m
B
Question: 8 machines can do a work in 10days. How many machines are needed to complete the work in 40days?
A.2
B.6
C.4
D.7
Answer: A.2
Explanation: Required number of machines = 8*10/40 = 2
Answer is A
Question: Calculate the average marks of a student who obtained 56, 60, 72, 85 and 80 marks (out of 100) in Geography, History and Government, Art, Computer Science and Modern Literature ?
A.71.6
B.70.6
C.80.6
D.60.6
Answer: B.70.6
Explanation: Explanation:
Average = (56+60+72+85+80 )/ 5 = 70.6.
Answer: B) 70.6
Question: If 20,371 + x is a multiple of 4, which of the following could be the value of x?
A.1
B.2
C.3
D.4
Answer: C.3
Explanation: Sum of the digits of 20,371 is 2+0+3+7+1 = 13
Now 13 is not a multiple of 4, the next multiple of 4 close to 13 is 16, which is 3 added to 13.
So the least number to be added to 20,371 is 3.
C
Question: The least number which when divided by 5, 6 , 7 and 8 leaves a remainder 3, but when divided by 9 leaves no remainder, is:
A.2377
B.1683
C.2677
D.9972
Answer: B.1683
Explanation: Explanation:
L.C.M. of 5, 6, 7, 8 = 840.
{\color{Blue} \therefore } Required number is of the form 840k + 3
Least value of k for which (840k + 3) is divisible by 9 is k = 2.
{\color{Blue} \therefore } Required number = (840 x 2 + 3) = 1683.
Answer: B) 1683
Question: Plane leaves from Chelsea every 50 minutes from West Ham airport. Air hostess told Frank Lampard that the plane had left 25 minutes ago and the next plane for Chelsea will leave at 7:00 p.m.
At what time air hostess convey this information to Frank Lampard?
A.6:35 pm
B.4:35 pm
C.4:35 pm
D.7:35 pm
Answer: A.6:35 pm
Explanation: A
6:35 pm
Time of Frank Lampard last missed plane = 7:00 p.m - 50 min = 6:10 p.m
As this information has been given to Frank Lampard 15 minutes after the plane has already left, the air hostess gave the information at 6:10 p.m + 25 min = 6:35 p.m
Question: A number a is squared and then multiplied by negative 3. The result of this operation is equal to three times the sum of three times a and two. What is one possible value of a ?
A.-3
B.-2
C.1
D.2
Answer: D.2
Explanation: -3*a^2=3(3a+2)
a= -2 or -1
a=-2=B
ANSWER:D
Question: The value of a machine depreciates at the rate of 10% per annum. If its present value is Rs. 81000, what will be its worth after 2 ears? What was the value of the machine 2 years ago?
A.Rs 65610,Rs 100000
B.Rs 64320,Rs 120000
C.Rs 60000,Rs 90000
D.Rs 72690,Rs 95700
Answer: A.Rs 65610,Rs 100000
Explanation: Explanation :
Solution: Value of the machine after 2 years = Rs.[81000(1 - 10/100)^2]
= Rs. 81000*9/10 * 9/10 = Rs. 65610.
Value of the machine 2 years ago = Rs. 81000/(1 - 10/100)^2
= Rs. 81000 * 10/9 * 10/9 = Rs. 100000
Answer : A
Question: The balance of a trader weighs 10% less than it should. Still the trader marks up his goods to get an overall profit of 20%. What is the mark up on the cost price?
A.40%
B.8%
C.25%
D.16.66%
Answer: B.8%
Explanation: Original cost before weight adjustment: X
Cost after 90% weight adjustment: 9/10 X
20% profit on 9/10X: (120/100)(9/10)(X) or 108X/100
Mark up on original cost of X: (108X/100)/X-1 = 8/100
ANSWER:B
Question: What is the probability of getting a number less than 4 when a die is rolled?
A.5/5
B.1/2
C.5/1
D.5/7
Answer: B.1/2
Explanation: Total number of outcomes possible when a die is rolled = 6 (∵ any one face out of the 6 faces)
i.e., n(S) = 6
E = Getting a number less than 4 = {1, 2, 3}
Hence, n(E) = 3
The probability = 3/6 = 1/2.
Answer: B
Question: There are a total of 17 students in Mr. David's gym class. Over the course of a badminton unit, each of the 17 students will compete exactly once against every other student in the class. How many total games of badminton will be played?
A.138
B.136
C.190
D.210
Answer: B.136
Explanation: there are 17 students , if each play with all other members .
then total games can be calculated as 16+15....+1 = 136.
alternate approach is to choose 2 distinct out of 17 = 17c2 = 136
Answer is B.
Question: A company organzied a help desk.there have been done 24 hrs work on software,17 hrs on help user nd 40% on other services.find the total no. of hrs have been worked on that day?
A.68
B.69
C.70
D.67
Answer: A.68
Explanation: let total no of hrs = x
they have done 24+17=41
40% of x is 40/100=2/5
x=41+2x/5
x=68.3
ANSWER:A
Question: Rs.4500 amounts to Rs.5544 in two years at compound interest, compounded annually. If the rate of the interest for the first year is 12%, find the rate of interest for the second year?
A.100%
B.1%
C.10%
D.0.1%
Answer: B.1%
Explanation: Let the rate of interest during the second year be R%. Given,
450 * {(100 + 12)/100} * {(100 + R)/100} = 5544
R = 1%
ANSWER:B
Question: At what angle the hands of a clock are inclined at 15 minutes past 5?
A.58 1/2 º
B.64º
C.67 1/2 º
D.72º
Answer: C.67 1/2 º
Explanation: Angle traced by hour hand in 21 hrs ={(360/12)x(21/4)}º =157 1/2 º Angle traced by min. hand in 15 min. ={(360/60)x 15}º = 90º. Required angle = 157 1/2	º - 90º = 67 1/2ºAnswer : C
Question: A, B and C enter into a partnership. They invest Rs. 50,000, Rs. 80,000 and Rs. 1,20,000 respectively. At the end of the first year, B withdraws Rs. 40,000, while at the end of the second year, C withdraws Rs. 80,000. In what ratio will the profit be shared at the end of 3 years ?
A.16 : 14 : 8
B.15 : 16 : 28
C.15 : 4 : 28
D.3 : 4 : 1
Answer: B.15 : 16 : 28
Explanation: A : B : C = (50000 x 36) : (80000 x 12 + 40000 x 24) : (120000 x 24 + 40000 x 12)
= 180 : 192 : 336
= 15 : 16 : 28.
Answer: B
Question: The average weight of 8 sailors in a boat is increased by 1 kg if one of them weighing 56 kg is replaced by a new sailor. The weight of the new sailor is?
A.57 kg
B.60 kg
C.64 kg
D.62 kg
Answer: C.64 kg
Explanation: The sailor weighing 56 kg is replaced and the average is increased by 1 kg.
Hence, the weight of the new sailor is (56 + increase in total weight)
= 56 +1 x 8
= 56 + 8 = 64 kg.
ANSWER:C
Question: A boy multiplied 987 by a certain number and obtained 559981 as his answer. If in the answer both 9 are wrong and the other digits are correct, then the correct answer would be:
A.553681
B.555181
C.555681
D.556581
Answer: C.555681
Explanation: 987 = 3 x 7 x 47
So, the required number must be divisible by each one of 3, 7, 47
553681->(Sum of digits = 28, not divisible by 3)
555181->(Sum of digits = 25, not divisible by 3)
555681 is divisible by 3, 7, 47
ANSWER C
Question: Express of the following as a fraction:
45%
A.14/25
B.9/20
C.9/40
D.9/19
Answer: B.9/20
Explanation: 45% = 45/100= 9/20.
Answer is B.
Question: 39 men can complete a piece of work in 18 days. In how many days will 27 men complete the same work ?
A.24
B.77
C.26
D.25
Answer: C.26
Explanation: Explanation:
Less Men, means more Days {Indirect Proportion}
Let the number of days be x
then,
27 : 39 :: 18 : x
[Please pay attention, we have written 27 : 39 rather than 39 : 27, in indirect proportion, if you get it then chain rule is clear to you :)]
{\color{Blue} x=\frac{39\times 18}{27}}
x = 26
So 26 days will be required to get work done by 27 men.
Answer: C
Question: A store has 10 bottles of juice, including 5 bottles of apple juice. In the evening, 6 bottles of juice are sold one by one. What is the probability of selling 4 bottles of apple juice among the 6 bottles? Assume that every bottle has an equal chance of being bought.
A.2/7
B.3/11
C.4/15
D.5/21
Answer: D.5/21
Explanation: The total number of ways to sell 6 bottles from 10 is 10C6 = 210.
The number of ways to sell 4 bottles of apple juice is 5C4*5C2 = 5*10 = 50
P(selling 4 bottles of apple juice) = 50/210 = 5/21
The answer is D.
Question: Last year a worker saved 6% of her annual salary. This year, she made 20% more money than last year and she saved 5% of her salary. The amount she saved this year was what percent of the amount she saved last year?
A.90%
B.100%
C.110%
D.120%
Answer: B.100%
Explanation: Let x be the worker's salary last year.
Last year, she saved 0.06x.
This year, she saved 0.05(1.2x)=0.06x
0.06x/0.06x=100%
The answer is B.
Question: A call center has two teams. Each member of Team A was able to process 6/5 calls as compared to each member of Team B. If Team A has 5/8 as many number of call center agents as Team B, what fraction of the total calls was processed by Team B?
A.3/2
B.3/4
C.4/7
D.1/2
Answer: C.4/7
Explanation: Let team B has 8 agents, so team A has 5 agents
Let each agent of team B picked up 5 calls, so total calls by team B = 40
So, each agent in Team A picked up 6 calls, so total calls for team A = 30
Fraction for team B = 40/(40+30) = 4/7 = Answer = C
Question: A train 520 meters long is running with a speed of 34 kmph. The time taken by it to cross a tunnel 280 meters long is?
A.287 sec
B.89 sec
C.48 sec
D.16 sec
Answer: B.89 sec
Explanation: D = 580 + 280 = 800
S = 34 * 5/18 = 9 mps
T = 800/9 = 89 sec
Answer: B
Question: P is four times as fast as Q and working together, they can complete a work in 5 days. In how many days can Q alone complete the work?
A.5 3/4 days
B.6 1/4 days
C.16 days
D.25 days
Answer: B.6 1/4 days
Explanation: P = 4Q
P + Q = 4Q + Q = 5Q
These 5Q people can do the work in 5 days, which means Q can do the work in 25 days.
Hence, P can do the work in 6 1/4 days.
ANSWER:B
Question: If y exceeds x by 60%, then x is less than y by?
A.1/2%
B.1/3%
C.1/4%
D.1/5%
Answer: A.1/2%
Explanation: X=100	y=160
160------60
100-------? => 37 1/2%
Answer:A
Question: The ratio between the radii of two spheres is 1:3. Find the ratio between their volumes?
A.1:28
B.1:27
C.1:29
D.1:39
Answer: B.1:27
Explanation: Explanation:
r1 : r2 = 1:3
r13 : r23 = 1:27
Answer: Option B
Question: A plane travels in the shape of equilateral triangle have sped of 20km/hr, 40km/hr and 60km/hr. Find the average speed of the palne.
A.42.73 km/h
B.52.73 km/h
C.32.73 km/h
D.62.73 km/h
Answer: C.32.73 km/h
Explanation: average speed = total distance/total time taken
=(d+d+d)/[(d/20)+(d/40)+(d/60)] where d= side of eq. triangle
=3d/d[1/20 + 1/40 + 1/60]
=3*20*40*60/[20*40+40*60+20*60]
= 360/11 km/h
= 32.73 km/h
ANSWER:C
Question: How much water must be added to 10 gallons of 10% brine solution to decrease the concentration to 8%?
A.0—1.5 gal
B.1.5—3 gal
C.3—4.5 gal
D.4.5—6 gal
Answer: B.1.5—3 gal
Explanation: Let amount of water that must be added in gallons to dilute concentration of brine solution = x
Amount of brine already present = 10/100 * 10 = 1 gallon
1/(10+x) *100 = 8
=>100 = 80 + 8x
=> x= 20/8 = 2.5
Answer B
Question: A train running at the speed of 60 km/hr crosses a pole in 18 sec. What is the length of the train?
A.287
B.699
C.677
D.300
Answer: D.300
Explanation: Speed = 60 * 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 15 = 300 m
Answer: D
Question: In a kilometre race, A can give B a start of 100 m or 15 seconds. How long does A take to complete the race?
A.150 seconds
B.165 seconds
C.135 seconds
D.66.67 seconds
Answer: C.135 seconds
Explanation: Explanatory Answer
In a 1000 metre race A gives B a start of 100 m or 15 seconds.
This essentially means that B takes 15 seconds to run 100 m.
Therefore, B will take 150 seconds to run the stretch of 1000 metres. (1000 m = 10 times 100 m and therefore the time taken will also be 10 times 15 seconds = 150 seconds).
As A gives B a start of 15 seconds, A obviously takes 15 seconds less than B to complete the race.
Hence, A will take 135 seconds to run the 1000 m.
Answer C
Question: Find the surface area of a cuboid 16 m long, 14 m broad and 7 m high
A.868 sq.cm
B.920 sq.cm
C.727 sq.cm
D.900 sq.cm
Answer: A.868 sq.cm
Explanation: Explanation:
Surface area = [2 (16 x 14 + 14 x 7 + 16 x 7)] cm2 = (2 x 434)cm2 = 868 cm2.
Answer: A
Question: A student took 6 courses last year and received an average (arithmetic mean) grade of 100 points. The year before, the student took 5 courses and received an average grade of 60 points. To the nearest tenth of a point, what was the student’s average grade for the entire two-year period?
A.79
B.89
C.95
D.81.81
Answer: D.81.81
Explanation: Let the 6 courses that were taken last year be A1 , A2, A3 , A4 , A5 , A6
A1+A2+A3+A4+A5+A6 = 100*6 = 600
The year before , the 5 courses be B1, B2 , B3 , B4 , B5
B1+B2+B3+B4+B5 = 60*5 = 300
Student's average = (600+300)/11 = 81.81
Answer D
Question: In how many ways 8 different tickets E can be distributed between Jane and Bill if each is to receive any even number of tickets and all 8 tickets to be distributed.
A.From 2 to 6 inclusive.
B.From 98 to 102 inclusive.
C.From 122 to 126 inclusive.
D.From 128 to 132 inclusive.
Answer: D.From 128 to 132 inclusive.
Explanation: Possibilities
J 8 6 4 2 0
B 0 2 4 6 8
# of ways 8C8 8C6 8C4 8C2 8C0
E=1+28+70+28+1 = 128 Answer is D.
Question: How many such letter-pairs are there in the word FRONTIER having same no. of letters left between them as they have in the series?
A.2
B.4
C.1
D.3
Answer: A.2
Explanation: We have to find whether for any letter-pair in this word, the same no. of letters exist between them in the alphabet series as that in this word.
So, consider ON - They are consecutive letters in the alphabet series as well as in this word.
Also consider NR - There exists 3 letter between them in the alphabets as O, P, Q. In this word also, there exists 3 letter between them (T, I, E).
So ans is 2
ANSWER:A
Question: Two varieties of wheat - A and B costing Rs. 9 per kg and Rs. 15 per kg were mixed in the ratio 3 : 7. If 5 kg of the mixture is sold at 25% profit, find the profit made?
A.Rs.12:29
B.Rs.18:90
C.Rs.16.28
D.Rs.16.50
Answer: D.Rs.16.50
Explanation: Let the quantities of A and B mixed be 3x kg and 7x kg.
Cost of 3x kg of A = 9(3x) = Rs. 27x
Cost of 7x kg of B = 15(7x) = Rs. 105x
Cost of 10x kg of the mixture = 27x + 105x = Rs. 132x
Cost of 5 kg of the mixture = 132x/10x (5) = Rs. 66
Profit made in selling 5 kg of the mixture = 25/100 (cost of 5 kg of the mixture) = 25/100 * 66 = Rs. 16.50
Answer:D
Question: 50% of a number is more than 40% of 120 by 180. Find the number?
A.456
B.480
C.420
D.445
Answer: A.456
Explanation: (50/100) * X – (40/100) * 120 = 180
1/2 X = 228
X = 456
Answer:A
Question: 14 times a number gives 210. The number is
A.11
B.12
C.15
D.None
Answer: C.15
Explanation: Explanation:
Let the number be 'N'
14×N=210⇒N=15
Correct Option: C
Question: One drier dries certain quantity of material in 24 minutes. Another drier does the same work in 2 minutes how much time will it take to do the same job when both driers are put to work ?
A.1.00 minutes
B.1.20 minutes
C.1.50 min
D.1.85 min
Answer: D.1.85 min
Explanation: By guess it is clear that the time taken will be less than 2 minutes and more than 1.5 mintes Therefore, answer 1.85 minutes will be correct. Answer-D
Question: If a car had traveled 25 kmh faster than it actually did, the trip would have lasted 30 minutes less. If the car went exactly 75 km, at what speed did it travel?
A.30 kmh
B.40 kmh
C.45 kmh
D.50 kmh
Answer: D.50 kmh
Explanation: Time = Distance/Speed
Difference in time = 1/2 hrs
75/x - 75/(x + 25) = 1/2
Substitute the value of x from the options. --> x = 50 --> 75/50 - 75/75 = 3/2 - 1 = 1/2
Answer: D
Question: In a class everyone will play at least one sport viz table tennis, cricket and badminton. 73
students play table tennis, 79 play badminton, 75 play cricket and 25 students play both table
tennis and badminton, 24 play both table tennis and cricket 30 play. Badminton and cricket and
17 students play all the sports. How many students play only cricket ?
A.35
B.38
C.39
D.47
Answer: A.35
Explanation: PERSONS PLAY CRICKET ONLY=N(C)-N(B∩C)+N(C∩T)-2(N(B∩T∩C))
=75-30+24-(2*17)
=35
ANSWER:A
Question: After 95 liters of petrol were poured into the tank, it was still 5% empty. How much petrol must be poured into the tank in order to fill it?
A.7 liters
B.4 liters
C.3 liters
D.5 liters
Answer: D.5 liters
Explanation: 95% ----------- 95
5% ------------ ?
=> 5 liters
Answer: D
Question: In a school 10% of the boys are same in number as 1/2th of the girls. what is the ratio of boys to the girls in the school?
A.5:1
B.2:3
C.1:4
D.3:7
Answer: A.5:1
Explanation: 10% of B = 1/2 G
10B/100 = G/2
B = 5G/1
B/G = 5/1
B:G = 5:1
Answer is A
Question: In case P there are 2 red pens and 3 blue pens, in case Q there is 1 red pen and 4 blue pens. A case is randomly picked, what is the probability of picking up a red pen from case Q?
A.1/10.
B.4/5.
C.3/10.
D.3/5.
Answer: A.1/10.
Explanation: Probability of picking up one case out of two= 1/2
probability of picking 1 red pen from case Q= 1/5
Hence the desired probability= 1/2*1/5= 1/10
A is the answer
Question: A team of eight entered for a shooting competition. The best marks man scored 85 points. If he had scored 92 points, the average scores for. The team would have been 84. How many points altogether did the team score?
A.665
B.700
C.720
D.730
Answer: A.665
Explanation: Explanation:
8 * 84 = 672 – 7 = 665
A)
Question: The organizers of a fair projected a 25 percent increase in attendance this year over that of last year, but attendance this year actually decreased by 20 percent. What percent of the projected attendance was the actual attendance?
A.45%
B.56%
C.64%
D.75%
Answer: C.64%
Explanation: Last year attendance = 100 (assume);
Projected Attendance = 125;
Actual Attendance = 80.
The actual attendance therefore was (Actual)/(Project) = 80/125 *100 = 64$ of the projected attendance.
Answer: C.
Question: A train 110 m long is running with a speed of 30 km/hr. In what time will it pass a man who is running at 6 km/hr in the direction opposite to that in which the train is going?
A.7 sec
B.6 sec
C.8 sec
D.11 sec
Answer: D.11 sec
Explanation: Speed of train relative to man = 30 + 6
= 36 km/hr.
= 36 * 5/18 = 10 m/sec.
Time taken to pass the men = 110 /10
=11 sec.
Answer:D
Question: A and B can do a piece of work in 8 days. With the help of C they finish the work in 4 days. C alone can do that piece of work in?
A.40 days
B.20 days
C.8 days
D.60 days
Answer: C.8 days
Explanation: C
8 days
C = 1/4 – 1/8 = 1/8 => 8 days
Question: When a certain number X is divided by 143, the remainder is 42. Which of the following numbers, if added to X, would result in a number divisible by 13?
A.10
B.21
C.34
D.47
Answer: A.10
Explanation: Now X= 143q + 42 = 11*13*q + 42..so we have to make only 42 div by 13..
42 +10 = 52 YES
minimum 10 to be added
A
Question: Solution A is 20% chlorine and Solution B is 80% chlorine. If you have 30 ounces of solution A and 60 ounces of solution B, in what ratio could you mix Solution A with Solution B to produce 50 ounces of a 50% chlorine solution?
A.6:4
B.6:14
C.4:4
D.4:6
Answer: C.4:4
Explanation: Forget the volumes for the time being.
You have to mix 20% and 80% solutions to get 50%. This is very straight forward since 50 is int he middle of 20 and 80 so we need both solutions in equal quantities. If this doesn't strike, use
w1/w2 = (A2 - Aavg)/(Aavg - A1)
w1/w2 = (80 - 50)/(50 - 20) = 1/1
So the volume of the two solutions will be equal. Answer has to be 4:4=C
Question: Find the number, the second digit of which is smaller than its first digit by 4, and if the number was divided by the digit’s sum, the quotient would be 7.
A.64
B.74
C.84
D.87
Answer: C.84
Explanation: 84 is the desired number.
84/12 =7
ANSWER:C
Question: There is a 40% chance that Betty will visit Denmark this year, while there is a 30% chance that she will visit Peru this year. What is the probability that Betty will visit either Denmark or Peru this year, but NOT both?
A.44%
B.46%
C.48%
D.50%
Answer: B.46%
Explanation: P(Denmark but not Peru)=0.4*0.7=0.28
P(Peru but not Denmark)=0.3*0.6=0.18
P(Denmark or Peru but not both)=0.28+0.18=0.46
The answer is B.
Question: The ratio of the arithmetic mean of two numbers to one of the numbers is 5:7. What is the ratio of the smaller number to the larger number?
A.2:3
B.2:5
C.3:7
D.4:9
Answer: C.3:7
Explanation: For two numbers, the arithmetic mean is the middle of the two numbers.
The ratio of the mean to the larger number is 5:7, thus the smaller number must have a ratio of 3.
The ratio of the smaller number to the larger number is 3:7.
The answer is C.
Question: At a tanning salon, customers are charged $10 for their first visit in a calendar month and $5 for each visit after that in the same calendar month. In the last calendar month, 100 customers visited the salon, of which 30 made a second visit, and 10 made a third visit. All other customers made only one visit. If those visits were the only source of revenue for the salon, what was the revenue for the last calendar month at the salon?
A.$1220
B.$1200
C.$1300
D.$1340
Answer: B.$1200
Explanation: I get B. This question seems too straightforward for 600+. Am I missing something?
100 first-time visits --> 100(10) = $1000
30 + 10 = 40 subsequent visits --> 40(5) = $200
Total revenue: 1000+ 200 = $1200
The answer is B.
Question: Light glows for every 16 seconds . How many times did it between 1:57:58 and 3:20:47 am
A.311
B.322
C.313
D.314
Answer: A.311
Explanation: the diff in sec between 1:57:58 and 3:20:47 is 4969 sec, 4969/16 = 310.
so total 311 times light ll glow
ANSWER:A
Question: A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If four marbles are picked at random, what is the probability that none is blue?
A.33/95
B.33/91
C.33/94
D.33/16
Answer: B.33/91
Explanation: Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles. When four marbles are picked at random, then the probability that none is blue is
= ¹²C₄/¹⁵C₄ = (12 * 11 * 10 * 9)/(15 * 14 * 13 * 12)
= 33/91
Answer:B
Question: A bag contains 12 white and 18 black balls. 2balls are drawn in succession. What is the probability that first is white and second is black?
A.35/145
B.36/145
C.36/140
D.36/141
Answer: B.36/145
Explanation: The probability that first ball is white:
=12C130C1=12C130C1
=1230=1230
=25=25
Since, the ball is not replaced; hence the number of balls left in bag is 29.
Hence, the probability the second ball is black:
=18C129C1=18C129C1
=1829=1829
Required probability,
=(25)×(1829)=(25)×(1829)
=36/145
B
Question: What is the area of square field whose side of length 15 m?
A.225
B.777
C.266
D.288
Answer: A.225
Explanation: 15 * 15 = 225 sq m
Answer: A
Question: If seven numbers are randomly selected without replacement from set {1, 2, 3, 4, 5, 6, 7}, what is the probability that the numbers are selected in ascending order?
A.1/2560
B.1/6400
C.1/4820
D.1/5040
Answer: D.1/5040
Explanation: The total number of ways to arrange 7 numbers is 7! = 5040.
There is only one way to arrange the numbers in ascending order.
P(ascending order) = 1/5040
The answer is D.
Question: Solution x contains 75% water and 25% oil; how many more liters of water than liters of oil are in 200 liters of solution x?
A.50
B.100
C.125
D.150
Answer: B.100
Explanation: water = .75 * 200=3/4 of 200=150
oil = .25*200=1/4 of 200=50
difference= 150 - 50=100
ANSWER:B
Question: In a jar there are balls in different colors: blue, red, green and yellow.
The probability of drawing a blue ball is 1/5.
The probability of drawing a red ball is 1/5.
The probability of drawing a green ball is 1/10.
If a jar cannot contain more than 50 balls, how many yellow balls are in the Jar?
A.5.
B.4.
C.3.
D.2.
Answer: A.5.
Explanation: We need to get some number which is less than 50 and exactly divisible by 5,5 and 10
Lets take LCM of three balls 5,5 and 10 = 10.
The probability of drawing a blue ball is 1/5...For every 8 balls we get 1 BLUE ball then out of 10 balls we get 2 BLUE balls.
The probability of drawing a red ball is 1/5...For every 5 balls we get 1 RED ball then out of 10 balls we get 2 REB balls.
The probability of drawing a green ball is 1/10. For every 10 balls we get 1 GREEN ball then out of 10 balls we get 1 GREEN BALLS.
Then out of 10 - ( 2 + 2 + 1 ) = 5 YELLOW balls.
IMO option A is correct.
Question: How many numbers from 45 to 110 are exactly divisible by 12?
A.5
B.7
C.6
D.11
Answer: C.6
Explanation: Option 'C'
45/12 = 3 and 110/12 = 9 ==> 9 - 3 = 6 Numbers