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.

Questions and Answers

Q 1 - Two funnels can fill a tank in 20 minutes and 30 minutes separately. On the off chance that both the channels are opened at the same time, then the tank will be filled in:

A - 10 min

B - 12 min

C - 15 min

D - 25 min

Answer : B

Explanation

Part filled by both pipes in 1 min. =(1/20+ 1/30)= 5/60  = 1/12
Time taken to fill the tank = 12 minutes

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:

A - 10 min

B - 12 min

C - 15 min

D - 20 min

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?

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 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 - 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 - Two pipes A and B can ill a tank in 36 hours and 45 hours respectively. If both the pipes are opened simultaneously, how much time will be taken to fill the tank?

A - 10 hours

B - 15 hours

C - 18 hours

D - 20 hours

Answer : D

Explanation

T = xy/(x+y)
= (36*45)/(36+45)
= 1620/80
= 20 hours

Or,

Part filled by A in 1 hour = 1/36
Part filled by B in 1 hour = 1/45
Part filled by (A+B) in 1 hour = (1/36 + 1/45) = 1/20

∴ Both the pipes can fill the tank in 20 hours.

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 - 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?

A - after 10 mins

B - after 12 min

C - after 20 min

D - after 8 min

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
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