Competitive Exams : Quantitative Aptitude - Pipes and Cistern (Set 10) | Concept of Maths

Question 1

Two pipes A and B can fill a cistern in 15 hours and 20 hours respectively, while a third pipe C can empty the full cistern in 25 hours. All three pipes are opened in the beginning. After 10 hours, C is closed. In how much total time will the cistern be full?

Accepted Answer

B) 12 hours

Answer

A) 13 hours

Answer

C) 11 hours

Answer

D) 14 hours

Question 2

A cistern has three pipes A, B, and C. A and B can fill it in 3 hours and 4 hours respectively, while C can empty it in 1 hour. If the pipes are opened in order at 3:00 PM, 4:00 PM, and 5:00 PM respectively on the same day, at what time will the cistern be empty?

Accepted Answer

D) 7:12 PM

Answer

A) 8:12 PM

Answer

B) 7:30 PM

Answer

C) 6:12 PM

Question 3

A pipe can fill a tank in 24 hours. Due to a leak in the bottom, it takes 36 hours to fill it. If the tank is full, how much time will the leak take to empty the full tank?

Accepted Answer

B) 72 hours

Answer

A) 60 hours

Answer

C) 84 hours

Answer

D) 48 hours

Question 4

Three pipes A, B, and C can fill a tank in 6 hours. After working together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. How many hours will C alone take to fill the tank?

Accepted Answer

C) 14 hours

Answer

A) 16 hours

Answer

B) 12 hours

Answer

D) 10 hours

Question 5

Two pipes A and B can fill a tank in 12 minutes and 15 minutes respectively. An outlet pipe C can empty the full tank in 20 minutes. If all three pipes are opened together, but pipe B is closed 3 minutes before the tank is full, what is the total time taken to fill the tank?

Accepted Answer

A) 12 minutes

Answer

B) 8 minutes

Answer

C) 10 minutes

Answer

D) 14 minutes

Question 6

Two pipes can fill a cistern in 14 hours and 16 hours respectively. The pipes are opened simultaneously, and it is found that due to a leakage in the bottom, it took 32 minutes longer to fill the cistern than the normal time. When the cistern is full, in how much time will the leak empty it?

Accepted Answer

C) 112 hours

Answer

A) 128 hours

Answer

B) 120 hours

Answer

D) 96 hours

Question 7

Pipe A is 3 times faster than Pipe B and therefore is able to fill a tank in 40 minutes less than Pipe B. If both the pipes are opened together, how much time will they take to fill the tank?

Accepted Answer

A) 15 minutes

Answer

B) 20 minutes

Answer

C) 18 minutes

Answer

D) 12 minutes

Question 8

A cistern can be filled by two pipes in 20 and 30 minutes respectively. Both pipes being opened, when must the first pipe be turned off so that the cistern may be just full in 15 minutes?

Accepted Answer

C) 10 minutes

Answer

A) 6 minutes

Answer

B) 12 minutes

Answer

D) 8 minutes

Question 9

A reservoir is fitted with two pipes A and B. A can fill it in 45 minutes and B can empty it in 1 hour. If they are opened on alternate minutes starting with A, how much time will it take to fill the reservoir?

Accepted Answer

C) 5 hours 53 minutes

Answer

A) 6 hours 12 minutes

Answer

B) 5 hours 30 minutes

Answer

D) 5 hours 45 minutes

Question 10

Three pipes A, B and C can fill a cistern in 10, 12 and 15 hours respectively. If pipe A is open all the time and B and C are opened for one hour each alternately, in how many hours will the cistern be full?

Accepted Answer

C) 5 7/10 hours

Answer

A) 5 hours

Answer

B) 6 hours

Answer

D) 6 1/2 hours

Question 11

Two pipes A and B can fill a tank in 24 minutes and 32 minutes respectively. If both pipes are opened together, after how many minutes should B be closed so that the tank is full in 18 minutes?

Accepted Answer

D) 8 minutes

Answer

A) 6 minutes

Answer

B) 10 minutes

Answer

C) 12 minutes

Question 12

A large tanker can be filled by two pipes A and B in 60 minutes and 40 minutes respectively. How many minutes will it take to fill the tanker from empty state if B is used for half the time and A and B fill it together for the other half?

Accepted Answer

A) 30 minutes

Answer

B) 35 minutes

Answer

C) 40 minutes

Answer

D) 25 minutes

Question 13

A tank has a leak which would empty it in 8 hours. A tap is turned on which admits 6 liters a minute into the tank, and it is now emptied in 12 hours. What is the capacity of the tank?

Accepted Answer

A) 8640 liters

Answer

B) 9000 liters

Answer

C) 7200 liters

Answer

D) 9600 liters

Question 14

Three taps A, B, and C can fill a tank in 12, 15, and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, starting with B on the first hour, how long will it take to fill the tank?

Accepted Answer

A) 7 hours

Answer

B) 6.5 hours

Answer

C) 7.5 hours

Answer

D) 6 hours

Question 15

Two pipes can fill a cistern in 37.5 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour if the second pipe B is turned off after how many minutes?

Accepted Answer

B) 9 minutes

Answer

A) 5 minutes

Answer

C) 15 minutes

Answer

D) 12 minutes

Question 16

A tap can fill a pool in 20 hours. After the pool is half full, three more similar taps are opened. What is the total time taken to fill the pool completely?

Accepted Answer

A) 12 hours 30 minutes

Answer

B) 15 hours

Answer

C) 11 hours 15 minutes

Answer

D) 13 hours 45 minutes

Question 17

A booster pump can be used to fill as well as empty a tank. The capacity of the tank is 2400 cubic meters. The emptying capacity of the pump is 10 cubic meters per minute higher than its filling capacity and the pump needs 8 minutes less to empty the tank than to fill it. What is the filling capacity of the pump?

Accepted Answer

D) 50 cubic meters per minute

Answer

A) 70 cubic meters per minute

Answer

B) 60 cubic meters per minute

Answer

C) 40 cubic meters per minute

Question 18

Two pipes A and B can fill a cistern in 12 hours and 16 hours respectively. A third pipe C can empty the full cistern in 24 hours. All three pipes are opened together. After 4 hours, Pipe B is closed. How much more time will it take for the remaining part of the cistern to be filled?

Accepted Answer

C) 14 hours

Answer

A) 16 hours

Answer

B) 18 hours

Answer

D) 12 hours

Question 19

Twelve identical taps can fill a reservoir in 20 minutes. If 4 taps go out of order, how long will it take for the remaining taps to fill the reservoir?

Accepted Answer

B) 30 minutes

Answer

A) 25 minutes

Answer

C) 35 minutes

Answer

D) 40 minutes

Question 20

A tank has three inlets A, B, and C. Pipe A can fill the tank in 8 hours, B in 12 hours, and C in 24 hours. All pipes are opened simultaneously. After 2 hours, pipe C is closed, and after another 2 hours, pipe B is closed. How much time does pipe A take to fill the rest of the tank alone?

Accepted Answer

A) 40 minutes

Answer

B) 30 minutes

Answer

C) 50 minutes

Answer

D) 45 minutes