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 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?

A - 96 hours

B - 102 hours

C - 106 hours

D - 112 hours

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?

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 - Three funnels A, B; C can fill a tank in 6 hours. In the wake of working at it together for 2 hours, C is shut and A and B can fill the remaining part in 7 hours. The quantity of hours taken by C alone to fill the tank is:

A - 10 hr.

B - 12 hr.

C - 14 hr.

D - 16 hr.

Answer : C

Explanation

Part filled by (A+B+c) in 2 hours= (1/6*2)=1/3
2/3 part is filled by (A+B) in 7 hours.
Whole is filled by (A+B) in (7*3/2) hr=21/2hrs.
Part filled by C in 1 hour = (1/6-2/21) = 3/42 = 1/14
∴C alone can fill it in 14 hours.

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 - Two pipes A and B can fill a water tank in 20 and 24 min respectively. A third pipe C can empty at the rate of 3 gallons per minute. If A, B and C opened together fill the tank in 15 min, the capacity of the tank (in gallons) is:

A - 180

B - 150

C - 120

D - 60

Answer : C

Explanation

Let the capacity of the tank = x gallons
Quantity of the water filled in the tank in 1 min when all the pipes A, B and C are opened simultaneously= x/20 + x/24 - 3
According to question,
x/20 + x/24 - 3 = x/15
or, x/20 + x/24 - x/15 = 3
or, (6x + 5x  - 8x)/120 = 3
or, 3x/120 = 3
or, x = 120 gallons

Q 10 - Taps A, B and C are connected to a water tank and the rate of flow of water is 42 ltr/hr, 56 ltr/hr and 48 ltr/hr respectively. A and ill fill the tank while tap C empties the tank. If the three taps are opened simultaneously, the tank gets filled up completely in 16 hours. What is the capacity of the tank?

A - 800 ltr

B - 960 ltr

C - 2346 ltr

D - None of these

Answer : A

Explanation

Net amount of water filled in 1 hr when all the pipes are opened simultaneously = 42 + 56 ? 48 = 50 ltr
Tank gets completely filled in 16 hrs.
∴ Capacity of tank = 16*50 = 800 liters.

aptitude_pipes_cisterns.htm
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