# Aptitude - Pipes & Cisterns Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to **Pipes & Cisterns**. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using **Show Answer** button. You can use **Next Quiz** button to check new set of questions in the quiz.

Q 1 - A tap can fill storage in 8 hours and another tap can discharge it in 16 hours. In the event that both the taps are open, the time taken to fill the tank will be:

### Answer : C

### Explanation

Net part filled in 1 hr = (1/8 ? 1/16)= 1/16 Total time taken to fill the tank = 16 hrs.

Q 2 - A channels can fill a tank in x hours and another funnel can exhaust it in y (y>x) hours. In the event that both the funnels are open, in how long will the tank be filled?

### Answer : D

### Explanation

Work done by filling pipe in 1 hr = 1/x Work done by emptying pipe in 1 hr = 1/y Net filling work done by both in 1 hr = (1/x- 1/y) = (y-x)/xy ∴The tank will be filled in xy/(y-x) hrs.

Q 3 - A funnel can discharge a tank in 40 minutes. A second pipe with distance across twice as much as that of the first is likewise joined with the tank to purge it. The two together can exhaust the tank in:

### Answer : B

### Explanation

A pipe with double diameter will take half time. So, the second pipe can empty the full tank in 20 min. Part emptied by both in 1 min. (1/40+ 1/20) = 3/40 Time taken to empty the full tank = 40/3 min.

Q 4 - Two pipes A and B can fill a tank in 15 minutes and 20 minutes separately. Both the channels are opened together. Be that as it may, following 4 minutes, pipe is turned off. What is the aggregate time required to fill the tank?

### Answer : D

### Explanation

Part filled by both in 4 min. = 4*(1/15+1/20)= (4*7/60)= 7/15 Part unfilled = (1-7/15) = 8/15 1/20 part is filled by B in 1 min. 8/15 part is filled by B in (20*8/15) min. = 32/3 min = 10 min 40 sec. Total time taken = (4 min+10 min 40 sec.) = 14 min 40 sec.

Q 5 - Two pipes A and B can fill a reservoir in 6 minutes and 7 minutes separately. Both the funnels are opened then again for 1 minute each. In what the reality of the situation will become obvious eventually fill the storage?

### Answer : C

### Explanation

Part filled by A in 1st min and B in 2nd min =(1/6+ 1/7 )= 13/42 Part filled by (A+B) working alternately in 6 min. (1/2 * 13/42*6) = 13/14 Remaining part = (1-13/14) = 1/14 It is now A's turn. 1/6 part is filled in 1 min. 1/14 part is filled in (6*1/14) min = 3/7 min. Total time taken = 45/7 min.

Q 6 - A tap can fill a tank in 6 hours. After a large portion of the tank is filled, three more comparable taps are opened. What is the aggregate time taken to fill the tank totally?

### Answer : B

### Explanation

Time taken by the tap to make the tank half full= 3 hrs. Remaining part = 1/2 Part filled by 4 taps in 1 hour= (4*1/6) = 2/3 2/3 part is filled in 1 hour. 1/2 part is filled in (3/2*1/2) hr = 3/4 hr = 45 min. Required time = 3hrs 45 min.

Q 7 - A storage has a hole which would exhaust it in 8 hours. A tap is transformed on which concedes 6 liters a moment into the reservoir and it is currently purged in 12 hours. What number of liters does the reservoir hold?

### Answer : D

### Explanation

Part filled in 1 hour = (1/8- 1/12)= 1/24 Time taken to fill the cistern= 24 hours Water moved in it 24 hours = (6*60*24) = 8640 liters. Capacity of the cistern = 8640 liters.

Q 8 - Pipes A and B can fill a tank in 10 hours each. A third pipe C empties the tank in 20 hours. If all the three pipes are opened simultaneously, in how much time will the tank be filled?

### Answer : B

### Explanation

Net part filled in 1 hour = (1/10 + 1/10 - 1/20) = (2+2-1) /20 = 3/20 ∴ Tank will be full in 20/3 = 18/3 hours = 6 hr 40 min

Q 9 - 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 the both the pipes are opened together when 3/4 of the cistern is already full of water.

### Answer : B

### Explanation

Part if cistern emptied in 1 hour = 1/5 - 1/8 = 3/40 3/40 part is emptied in hour. ∴ 3/4 part is emptied in 40/3 * 3/4 = 10 hour

Q 10 - Taps A and B can fill a bucket in 12 min and 15 min respectively. If both the taps are opened and tap A is closed after 3 mins, how much further time would it take for tap B to fill the bucket?

### Answer : B

### Explanation

Part of bucket filled by tap A and B together in 1 min = 1/12 + 1/15 = 3/20 ∴ Part of bucket filled by A and B in 3 min = 3*3/20 = 9/20 Remaining part = 1 - 9/20 = 11/20 Tap B can fill 11/20 part in 15*11/20 = 33/4 min = 8 min 15 sec