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 - In 1 minute 3/7 of a basin is filled. Whatever remains of the container can be filled in:
A - 2 min
B - 4/3 min
C - 7/3 min
D - none of these
Part filled in 1 min. = 3/7. remaining part = (1- 3/7)= 4/7
Let the required time be x min.
More part, more time taken. (Direct)
3/7: 4/7:: 1: x ⇒ 3x/7 = (4/7*1) ⇒ x= 4/3 min.
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
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
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 channels can fill a tank in 15 hours and 12 hours separately and a third pipe can purge it in 4 hours. In the event that the channels are opened all together at 8 am, 9 am and 11am separately, the tank will be exhausted at
A - 11.40 am
B - 12.40 pm
C - 1.40 pm
D - 2.40 pm
Let the tank be emptied in x hrs after 8 am.
Work done by A in x hrs, by B in (x-1) hrs and C in (x-3) hrs = 0
⇒x/15+ (x-1)/12- (x-3)/4 = 0 ⇒ 4x+5(x-1) - 15(x-3) = 0
⇒6x= 40 ⇒x= 20/3 hrs.
⇒x= 6 hrs. 40 min after 8 am
Hence the tank will be emptied at 14 hrs 40 min, i.e., 2:40 pm
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
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 - 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
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 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
A - 5260 ltr.
B - 5760 ltr.
C - 5846 ltr.
D - 6970 ltr.
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 - 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
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 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
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 - One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, the slower pipe alone will be able to fill the tank in ?
A - 81 mins
B - 108 min
C - 192 min
D - 144 min
Let the time taken by faster pipe be x min
∴ 1/x + 1/3x = 1/36
Or, (3 +1)/3x = 1/36
Or, x = 48 min

∴ Time taken by slower pipe to fill the tank = 3*48min = 144 min

    87 Lectures 
     22.5 hours 

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