Competitive Exams : Quantitative Aptitude - Pipes and Cistern (Set 9) | Concept of Maths

Question 1

Three pipes A, B, and C can fill a cistern in 12, 15, and 20 hours respectively. If pipe A is open all the time and B and C are open for one hour each alternately, in how many hours will the cistern be full?

Accepted Answer

B) 7 hours

Answer

A) 6.5 hours

Answer

C) 7.5 hours

Answer

D) 6 hours

Question 2

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

Accepted Answer

C) 8 minutes

Answer

A) 10 minutes

Answer

B) 6 minutes

Answer

D) 12 minutes

Question 3

A cistern has a leak which can empty it in 8 hours. A tap is turned on which admits 6 litres a minute into the cistern, and it is now emptied in 12 hours. How many litres does the cistern hold?

Accepted Answer

D) 8640 litres

Answer

A) 9000 litres

Answer

B) 7200 litres

Answer

C) 9600 litres

Question 4

A booster pump can be used for filling as well as for emptying 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 lesser to empty the tank than it needs to fill it. What is the filling capacity of the pump?

Accepted Answer

B) 50 cubic meters per minute

Answer

A) 70 cubic meters per minute

Answer

C) 40 cubic meters per minute

Answer

D) 60 cubic meters per minute

Question 5

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

Accepted Answer

A) 12 hours

Answer

B) 11 hours

Answer

C) 14 hours

Answer

D) 13 hours

Question 6

A large tank 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 tank from empty state if B is used for half the time and A and B fill it together for the other half?

Accepted Answer

C) 30 minutes

Answer

A) 20 minutes

Answer

B) 15 minutes

Answer

D) 24 minutes

Question 7

A leak in the bottom of a tank can empty the full tank in 6 hours. An inlet pipe fills water at the rate of 4 litres a minute. When the tank is full, the inlet is opened and due to the leak, the tank is empty in 8 hours. Find the capacity of the tank.

Accepted Answer

B) 5760 litres

Answer

A) 6480 litres

Answer

C) 6000 litres

Answer

D) 5260 litres

Question 8

Three pipes A, B, and C can fill a tank in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is:

Accepted Answer

B) 14 hours

Answer

A) 10 hours

Answer

C) 16 hours

Answer

D) 12 hours

Question 9

Two pipes A and B can fill a cistern in 15 hours and 18 hours respectively. Both pipes are opened together, but 3 hours before the cistern is full, pipe A is closed. In how much time will the cistern be filled?

Accepted Answer

D) 9 9/11 hours

Answer

A) 10 hours

Answer

B) 11 3/11 hours

Answer

C) 8 2/11 hours

Question 10

Two pipes A and B can fill a tank in 36 minutes and 45 minutes respectively. A waste pipe C can empty the tank in 30 minutes. First A and B are opened. After 7 minutes, C is also opened. In how much time is the tank full?

Accepted Answer

A) 46 minutes

Answer

B) 42 minutes

Answer

C) 39 minutes

Answer

D) 49 minutes

Question 11

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 leakage in the bottom, it took 32 minutes more to fill the cistern. When the cistern is full, in what time will the leak empty it?

Accepted Answer

D) 112 hours

Answer

A) 128 hours

Answer

B) 120 hours

Answer

C) 96 hours

Question 12

Pipe A can fill a tank in 16 minutes and Pipe B can empty it in 24 minutes. If both pipes are opened together, but after some time Pipe B is closed, the tank is filled in 30 minutes. For how many minutes was Pipe B kept open?

Accepted Answer

D) 21 minutes

Answer

A) 18 minutes

Answer

B) 15 minutes

Answer

C) 24 minutes

Question 13

Tap A fills a tank in 10 hours and Tap B empties it in 15 hours. Both are opened alternately for 1 hour each, starting with Tap A. In how many hours will the tank be full?

Accepted Answer

D) 55 hours

Answer

A) 57 hours

Answer

B) 60 hours

Answer

C) 56 hours

Question 14

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

Accepted Answer

C) 5 7/10 hours

Answer

A) 5 1/2 hours

Answer

B) 6 hours

Answer

D) 5 hours

Question 15

Two pipes A and B can fill a cistern in 12 min and 15 min respectively. There is also a waste pipe C. When all three are opened together, the empty cistern is full in 20 min. How long will the waste pipe take to empty the full cistern?

Accepted Answer

B) 10 min

Answer

A) 12 min

Answer

C) 8 min

Answer

D) 15 min

Question 16

An inlet pipe can fill a tank in 10 hours and an outlet pipe can empty it in 20 hours. Both pipes are opened at 6:00 AM. After 4 hours, the outlet pipe is closed. At what time will the tank be full?

Accepted Answer

A) 6:00 PM

Answer

B) 5:00 PM

Answer

C) 4:00 PM

Answer

D) 7:00 PM

Question 17

A cistern can be filled by two pipes A and B in 4 hours and 6 hours respectively. When full, the cistern can be emptied by a third pipe C in 8 hours. If all three pipes are turned on at the same time, the cistern will be full in:

Accepted Answer

B) 3 3/7 hours

Answer

A) 2 2/7 hours

Answer

C) 4 1/7 hours

Answer

D) 3 5/7 hours

Question 18

Eight taps are fitted to a water tank. Some of these are water taps to fill the tank and the remaining are outlet taps to empty the tank. Each water tap can fill the tank in 12 hours and each outlet tap can empty it in 36 hours. On opening all the taps, an empty tank is filled in 3 hours. Find the number of water taps.

Accepted Answer

C) 5

Answer

A) 6

Answer

B) 4

Answer

D) 3

Question 19

One fill pipe A takes 3 minutes more to fill a tank than pipes A and B together. Another fill pipe B takes 21 1/3 minutes more to fill the tank than A and B together. If both pipes are opened together, how long will they take to fill the tank?

Accepted Answer

A) 8 minutes

Answer

B) 6 minutes

Answer

C) 12 minutes

Answer

D) 10 minutes

Question 20

A tank is fitted with two inlet pipes A and B and one outlet pipe C. Pipe A can fill the tank in 12 hours, and Pipe B can fill it in 15 hours. C can empty the full tank in x hours. If all three pipes are opened together, the tank is filled in 10 hours. Find the value of x.

Accepted Answer

D) 20

Answer

A) 22

Answer

B) 18

Answer

C) 24