Competitive Exams : Quantitative Aptitude - Pipes and Cistern (Set 6) | Concept of Maths

Question 1

Two pipes A and B can fill a tank in 12 hours and 15 hours respectively. If both pipes are opened together, how much time will they take to fill the tank?

Accepted Answer

A) 6 hours 40 minutes

Answer

B) 7 hours 30 minutes

Answer

C) 6 hours 20 minutes

Answer

D) 8 hours

Question 2

A pipe can fill a cistern in 8 hours, but due to a leak at the bottom, it takes 10 hours to fill it. If the cistern is full, in how many hours can the leak empty it?

Accepted Answer

B) 40 hours

Answer

A) 30 hours

Answer

C) 35 hours

Answer

D) 45 hours

Question 3

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) 10 hours

Answer

B) 12 hours

Answer

D) 16 hours

Question 4

Pipe A can fill a tank in 20 minutes and Pipe B can fill it in 30 minutes. If both pipes are opened together, but after 8 minutes Pipe A is closed, how much longer will it take to fill the tank?

Accepted Answer

A) 10 minutes

Answer

B) 12 minutes

Answer

C) 8 minutes

Answer

D) 14 minutes

Question 5

A cistern can be filled by two pipes in 15 minutes and 12 minutes respectively, and emptied by a third pipe in 20 minutes. If all three pipes are opened together, in what time will the cistern be filled?

Accepted Answer

A) 10 minutes

Answer

B) 12 minutes

Answer

C) 15 minutes

Answer

D) 8 minutes

Question 6

Two pipes can fill a reservoir in 20 hours and 24 hours respectively, and a waste pipe can empty 3 gallons per minute. If all three pipes are opened together, they fill the reservoir in 15 hours. What is the capacity of the reservoir?

Accepted Answer

B) 7200 gallons

Answer

A) 6000 gallons

Answer

C) 8400 gallons

Answer

D) 5000 gallons

Question 7

A tap can fill a pool in 16 hours. Because of a leak, it takes 24 hours. If the pool is half full, how many hours will the leak take to empty it?

Accepted Answer

A) 24 hours

Answer

B) 36 hours

Answer

C) 48 hours

Answer

D) 12 hours

Question 8

A large reservoir has three pipes. Pipe X can fill it in 12 hours and Pipe Y in 15 hours, while Pipe Z can empty it in 20 hours. If they are opened at 8:00 AM, 9:00 AM, and 10:00 AM respectively, at what time will the reservoir be full?

Accepted Answer

A) 5:40 PM

Answer

B) 6:20 PM

Answer

C) 4:30 PM

Answer

D) 5:10 PM

Question 9

Two pipes can fill a tank in 15 hours and 12 hours respectively. A third pipe can empty it in 4 hours. If the pipes are opened in order at 8:00 AM, 9:00 AM, and 11:00 AM respectively, at what time will the tank be completely empty?

Accepted Answer

A) 2:40 PM

Answer

B) 1:20 PM

Answer

C) 2:20 PM

Answer

D) 1:40 PM

Question 10

Pipe A is four times as fast as Pipe B and can fill a tank in 15 minutes less than Pipe B. How much time will they take to fill the tank together?

Accepted Answer

A) 4 minutes

Answer

B) 5 minutes

Answer

C) 6 minutes

Answer

D) 8 minutes

Question 11

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 liters a minute. When the tank is full, the inlet is opened and due to the leak, the tank is emptied in 8 hours. What is the capacity of the tank?

Accepted Answer

A) 5760 liters

Answer

B) 6400 liters

Answer

C) 4800 liters

Answer

D) 5200 liters

Question 12

Two pipes can fill a cistern in 14 hours and 16 hours respectively. They are opened simultaneously, but a leak is found in the bottom, which takes 32 more minutes to fill the cistern. In how many hours can the leak alone empty the full cistern?

Accepted Answer

A) 112 hours

Answer

B) 96 hours

Answer

C) 80 hours

Answer

D) 128 hours

Question 13

A tank has three pipes, P, Q, and R. P and Q can fill it in 10 and 12 hours respectively, while R can empty it in 15 hours. If P is opened at 7 AM, Q at 8 AM, and R at 9 AM, what portion of the tank is filled at 11 AM?

Accepted Answer

A) 31/60

Answer

B) 41/60

Answer

C) 29/60

Answer

D) 7/12

Question 14

Two taps can separately fill a bath in 12 and 15 minutes respectively. They are both turned on together for 3 minutes, and then the first is turned off. How much longer will it take the second tap to fill the bath?

Accepted Answer

A) 8 minutes 15 seconds

Answer

B) 8 minutes 45 seconds

Answer

C) 7 minutes 30 seconds

Answer

D) 9 minutes

Question 15

A cistern is normally filled in 9 hours, but it takes 10 hours to fill when there is a leak in its bottom. If the cistern is full, in what time will the leak empty it?

Accepted Answer

A) 90 hours

Answer

B) 100 hours

Answer

C) 80 hours

Answer

D) 95 hours

Question 16

Three taps A, B, and C can fill an overhead tank in 4, 6, and 12 hours respectively. How long would they take to fill the tank if all three taps are opened together?

Accepted Answer

A) 2 hours

Answer

B) 3 hours

Answer

C) 2.5 hours

Answer

D) 4 hours

Question 17

One pipe can fill a pool three times as fast as another pipe. If together they can fill the pool in 12 hours, how many hours will the slower pipe take to fill it alone?

Accepted Answer

A) 48 hours

Answer

B) 36 hours

Answer

C) 40 hours

Answer

D) 45 hours

Question 18

A tank has an inlet pipe that can fill it in 8 hours and an outlet pipe that can empty it in 12 hours. If the outlet pipe is accidentally left open, how many hours will it take to fill the empty tank?

Accepted Answer

A) 24 hours

Answer

B) 20 hours

Answer

C) 16 hours

Answer

D) 30 hours

Question 19

Pipe A can fill a tank in 10 hours and Pipe B can empty it in 15 hours. Both are opened simultaneously. After 5 hours, the outlet pipe B is closed. How much more time is taken by Pipe A to fill the remaining tank?

Accepted Answer

A) 8 hours 20 minutes

Answer

B) 7 hours 30 minutes

Answer

C) 9 hours

Answer

D) 8 hours 45 minutes

Question 20

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 many hours will the cistern be full?

Accepted Answer

A) 12 hours

Answer

B) 11.5 hours

Answer

C) 13 hours

Answer

D) 12.5 hours