Competitive Exams : Quantitative Aptitude - Pipes and Cistern (Set 8) | Concept of Maths

Question 1

Two pipes A and B can fill a cistern in 12 hours and 15 hours respectively. If both pipes are opened together, how long will it take to fill the cistern?

Accepted Answer

B) 6 hours 40 minutes

Answer

A) 5 hours 20 minutes

Answer

C) 8 hours

Answer

D) 7 hours 30 minutes

Question 2

An inlet pipe can fill a pool in 8 hours, while an outlet pipe can empty the fully filled pool in 12 hours. If both pipes are opened simultaneously when the pool is completely empty, how many hours will it take to fill the pool?

Accepted Answer

D) 24 hours

Answer

A) 16 hours

Answer

B) 20 hours

Answer

C) 18 hours

Question 3

Three pipes P, Q, and R can fill a water tank in 10, 15, and 30 hours respectively. If all three pipes are opened at the same time, in how many hours will the tank be full?

Accepted Answer

D) 5 hours

Answer

A) 8 hours

Answer

B) 6 hours

Answer

C) 4 hours

Question 4

Pipe X can fill a reservoir in 6 hours, but due to a leak at the bottom of the reservoir, it takes 2 hours longer to fill it. In how many hours can the leak alone empty the full reservoir?

Accepted Answer

D) 24 hours

Answer

A) 18 hours

Answer

B) 16 hours

Answer

C) 12 hours

Question 5

Two pipes can fill a tank in 20 minutes and 30 minutes respectively. Both pipes are opened together, but after 5 minutes, the first pipe is turned off. How much longer will it take for the second pipe alone to fill the remaining part of the tank?

Accepted Answer

A) 17 and a half minutes

Answer

B) 20 minutes

Answer

C) 15 minutes

Answer

D) 12 minutes

Question 6

Pipe A is three times as fast as Pipe B in filling a cistern. If both pipes together can fill the cistern in 18 minutes, how long would Pipe B alone take to fill it?

Accepted Answer

B) 72 minutes

Answer

A) 54 minutes

Answer

C) 36 minutes

Answer

D) 48 minutes

Question 7

A cistern has two pipes. One can fill it with water in 8 hours and the other can empty it in 5 hours. In how many hours will the cistern be emptied if both the pipes are opened together when three-fourths of the cistern is already full of water?

Accepted Answer

D) 10 hours

Answer

A) 20 hours

Answer

B) 15 hours

Answer

C) 12 hours

Question 8

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

Accepted Answer

A) 14 hours

Answer

B) 12 hours

Answer

C) 16 hours

Answer

D) 10 hours

Question 9

Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both are opened together, but the inlet pipe A is closed 4 minutes before the tank is completely full. What is the total time taken to fill the tank?

Accepted Answer

B) 10 minutes 51 seconds

Answer

A) 12 minutes

Answer

C) 10 minutes

Answer

D) 11 minutes

Question 10

A tank has an inlet pipe that can fill it in 3 hours and an outlet pipe that can empty it in 6 hours. If they are opened on alternate hours starting with the inlet pipe, in how many hours will the tank be completely filled?

Accepted Answer

D) 9 hours

Answer

A) 11 hours

Answer

B) 10 hours

Answer

C) 8 hours

Question 11

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

Accepted Answer

B) 8 minutes

Answer

A) 6 minutes

Answer

C) 10 minutes

Answer

D) 12 minutes

Question 12

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 opened for one hour each alternately, in how many hours will the cistern be full?

Accepted Answer

C) 7 hours

Answer

A) 6 hours

Answer

B) 8 hours

Answer

D) 5 hours

Question 13

A leak in the bottom of a tank can empty the full tank in 8 hours. An inlet pipe fills water at the rate of 6 liters a minute. When the tank is full, the inlet is opened and due to the leak, the tank is empty in 12 hours. How many liters of water can the tank hold?

Accepted Answer

B) 8640 liters

Answer

A) 5760 liters

Answer

C) 9600 liters

Answer

D) 7200 liters

Question 14

Two pipes A and B can each fill a tank in 12 hours when working normally. Both pipes are opened together, but due to an obstruction, both pipes work at only half of their normal efficiency. If the obstruction is removed after some time and the tank is filled in a total of 8 hours from the start, for how long was the obstruction present?

Accepted Answer

D) 4 hours

Answer

A) 5 hours

Answer

B) 6 hours

Answer

C) 3 hours

Question 15

A large cistern can be filled by an inlet pipe in 15 hours. There are two outlet pipes of equal diameter, each capable of emptying the full cistern in 30 hours. If the inlet pipe and both outlet pipes are all opened together, in how many hours will the cistern be completely filled?

Accepted Answer

D) The cistern will never be filled

Answer

A) 45 hours

Answer

B) 30 hours

Answer

C) 15 hours

Question 16

A pipe can fill a tank in 16 hours. Because of a leak at the bottom of the tank, it takes 24 hours to fill the tank. If the tank is full, how long will it take for the leak to empty one-third of the tank?

Accepted Answer

A) 16 hours

Answer

B) 20 hours

Answer

C) 24 hours

Answer

D) 12 hours

Question 17

Twelve identical taps can fill a reservoir in 18 minutes. How many such taps can fill the same reservoir in 24 minutes?

Accepted Answer

D) 9 taps

Answer

A) 6 taps

Answer

B) 10 taps

Answer

C) 8 taps

Question 18

Pipe A can fill a tank in 9 hours, and Pipe B can fill it in 12 hours. If both pipes are opened together, and then Pipe A is closed after 3 hours, how much total time (from the start) will it take to fill the tank?

Accepted Answer

D) 8 hours

Answer

A) 7 hours

Answer

B) 6 hours

Answer

C) 9 hours

Question 19

One pipe fills a water tank three times faster than another pipe. If the two pipes together can fill the tank in 36 minutes, what is the time taken by the slower pipe alone to fill the tank?

Accepted Answer

C) 144 minutes

Answer

A) 108 minutes

Answer

B) 120 minutes

Answer

D) 160 minutes

Question 20

A pool has three pipes A, B, and C. Pipes A and B can fill the pool in 4 hours and 6 hours respectively, while Pipe C can empty the pool in 3 hours. If all three pipes are opened at 9:00 AM, at what time will the pool be completely filled?

Accepted Answer

A) 9:00 PM

Answer

B) 7:00 PM

Answer

C) 11:00 PM

Answer

D) 5:00 PM