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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 tank can be filled by a tap in 20 minutes and by another tap in an hour. Both the taps are kept open for 10 minutes and after that the first tap is shutoff. After this, the tank will be totally filled in:

Answer : D

Explanation

Part of the tank filled by both in 10 min. = 10*(1/20+1/60)= 40/60 = 2/3
Remaining part = (1-2/3) = 1/3
1/60 part is now filled in 1 min.
1/3 part is now filled in (60*1/3) min. = 20 min.

Q 3 - A storage has two funnels. One can fill it with water in 8hours and the other can exhaust it in 5 hours. In how long will the reservoir be purged if both the channels are opened together when 3/4 of the storage is now loaded with water?

Answer : C

Explanation

Net part emptied by both in 1 hr = (1/5-1/8)= 3/40
3/40 part is emptied in 1 hr.
3/4 part will be emptied in (40/3*3/4) hrs = 10 hrs.

Q 4 - Two funnels can fill a reservoir in 14hrs and 16 hrs. individually. The funnels are opened all the while and it is found that because of spillage in the last, 32 minutes additional are taken for the reservoir to be topped off. In the event that the storage is full, in what time would the release unfilled it?

Answer : D

Explanation

Work done by two pipes in 1 hr= (1/14+1/16)= 15/112
Total time taken by two pipes and leak in 1 hr= (112/15+32/60) hrs= 8 hrs.
Work done by the leak in 1 hr = (15/112- 1/8) = 1/112
Hence, the leak will empty the full cistern in 112 hrs.

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 substantial tanker can be filled by two pipes A and B in an hour and 40 minutes separately. How long will it take to fill the tanker from unfilled state if B is utilized for a fraction of the time and A and B fill it together for the other half?

Answer : D

Explanation

Let the total time taken be x minute. Then,
(1/40*x/2) + (1/60+ 1/40) x/2= 1 ⇒ x/80 + x/48 = 1
⇒3x+ 5x= 240 ⇒8x= 240 ⇒x= 30
Hence, the required time is 30 minutes.

Q 7 - A break in the base of a tank can purge the full tank in 6 hours. A channel funnel fills water at the rate of 4 liters for each moment. At the point when the tank is full, the channel is opened and because of the break, the tank is void in 8 hours. The limit of the tank is

Answer : B

Explanation

Part filled in 1 hour = (1/6-1/8)= 1/24
So, the inlet can fill the tank in 24 hours.
Capacity of the tank= volume of water that flows in 24 hrs
= (4*60*24) ltr. = 5760 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 - A cistern can be filled by two pipes in 20 and 30 min respectively. Both pipes being open, when must the first pipe be turned off so that so that the cistern may be filled in 10 min more?

Answer : D

Explanation

In 1 min both pipes can fill = 1/20 + 1/30
= 1/12
In 10 min second pipe can fill = (1/30)*10 = 1/3 part
Part of cistern filled by both the pipes = 1 - 1/3
= 2/3
1/12 part is filled in 1 min
∴ 2/3 part will be filled in 12*2/3 = 8 min
Hence, first first pipe should be turned off after 8 min.

aptitude_pipes_cisterns.htm