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 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?

A - 10/3 hours

B - 6 hours

C - 10 hours

D - 40/3 hours

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?

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 - A reservoir has three channels A, B and C. A and B can fill it in 3 hrs and 4 hrs. individually while C can exhaust the totally filled reservoir in 1 hours. On the off chance that the funnels are opened all together at 3 pm, 4 pm and 5 pm individually, at what the truth will surface eventually reservoir void?

A - 6.15 pm

B - 7.12 pm

C - 8.12 pm

D - 8.35 pm

Answer : B

Explanation

Let the cistern be emptied in x hrs after 3 pm
Work done by A in x hrs, by B in(x-1) hrs and by C in (x-2) hrs= 0
⇒x/3 +x-1/4 ? (x-2) =0 ⇒ 4x+3(x-1)-12(x-2) = 0
⇒5x=21 ⇒x= 4 hrs 12 min.
Required time is 7.12 pm.

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 - A channel can fill a reservoir in 12 minutes and another funnel can fill it in 15 minutes, however a third pipe can discharge it in 6 minutes. The initial two funnels are kept open for 5 minute to start with and after that the third pipe is additionally opened. In what time is the storage exhausted?

A - 30 minutes

B - 33 minutes

C - 75/2 minutes

D - 45 minutes.

Answer : D

Explanation

Part filled in 5 min= 5*(1/12+1/15)= (5*9/60)= 3/4
Part emptied in 1 min. when all the pipes are opened= 1/6 ? (1/12+1/15)
 = (1/6- 3/20) = 1/60
1/60 part is emptied in 1 min.
3/4 part will be emptied in (60*3/4) min = 45 min.

Q 9 - A pump can fill a tank with water in 2 hours. Because of a leak in the tank, it takes 7/3 hours to fill the tank. The leak can empty the filled tank in?

A - 8 hours

B - 7 hours

C - 7/3 hours

D - 14 hours

Answer : D

Explanation

Part of the tank filled by the pump in 1 hour = 1/2
Part of the tank filled by the pump in 1 hour because of the leak = 3/7
∴ Part of the tank emptied by the leak in 1 hour = 1/2 - 3/7
= 1/14
∴ Leak will empty the tank in 14 hours.

Q 10 - Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for 1 hour each alternatively, the tank will be full in -

A - 5 hr

B - 7.5 hr

C - 6 hr

D - 7 hr

Answer : D

Explanation

Tank filled by (A+B) in 1 hour = (1/12 + 1/15) = 3/20
Tank filled by (A+C) in 1 hr = (1/12 + 1/20) = 2/15

∴ Part of tank filled in 2 hr = (3/20 + 2/15) = 17/60
∴ Part of tank filled in 6 hr = (3*17/60) = 17/20

Remaining part = 1 - 17/20 = 3/20

Now it is the turn of A and B and 3/20 is filled by A and B in 1 hour.

∴ Total time taken to fill the tank = (6+1) = 7 hr


aptitude_pipes_cisterns.htm

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