Aptitude - Pipes & Cisterns Online Quiz



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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.

Questions and Answers

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:

A - 8 hours

B - 10 hours

C - 16 hours

D - 24 hours

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?

A - (x-y) hours

B - (y-x) hours

C - xy/(x-y) hours

D - xy/(y-x) hours

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:

A - 8 min

B - 40/3 min

C - 30 min

D - 38 min

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?

A - 10 min 20 sec

B - 11 min 45 sec

C - 12 min 30 sec

D - 14 min 40 sec

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?

A - 5 min

B - 17/3 min

C - 45/7 min

D - 5/4 min

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?

A - 3hrs 15 min.

B - 3 hrs 45 min.

C - 4 hrs

D - 4 hrs 15 min

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?

A - 7580 ltr.

B - 7960 ltr.

C - 8290 ltr.

D - 8640 ltr.

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?

A - 6 hr 30 min

B - 6 hr 40 min

C - 6 hr 20 min

D - 4 hr 40 min

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.

A - 13.5 hours

B - 10 hours

C - 6 hours

D - 3.5 hours

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?

A - 8 min 5 sec

B - 8 min 15 sec

C - 7 min 45 sec

D - 7 min 15 sec

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


aptitude_pipes_cisterns.htm

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