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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 - 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:

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 pump can fill a tank with water in 2 hours. In light of a break in the tank, it takes 7/3 hours to fill the tank. The hole can discharge the filled tank in:

Answer : D

Explanation

Part filled by the pump in 1 hr = 1/2
Net part filled by the pump and leak in 1 hr = 3/7
Emptying work done by the leak in 1 hr= (1/2 - 3/7)= 1/14
Leak can empty the tank in 14 hours.

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 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

Answer : D

Explanation

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 tank is fitted with two taps A and B. A can fill the tank totally in 45 minutes and B can purge the full tank in 60 minutes. On the off chance that both the taps are opened on the other hand for 1 minute, then in what amount of time the unfilled tank will be filled totally?

Answer : D

Explanation

Work done by A in 1st minutes and B 2nd minute= (1/45- 1/60)= 1/180
Part filled in 2 min = 1/180
Part filled in 358 min = (1/360*358) =   358/360 = 179/180
Remaining part = (1-179/180) = 1/180
1/45 part is filled by A in (45*1/180) min= 1/4 min.
Total time taken to fill it = 358 1/4 min = 5 hrs.58 min 15 sec.

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?

Answer : B

Explanation

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

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 - 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?

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 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 - Taps A and B can fill a bucket in 12 min and 15 min respectively. If both the taps are opened and tap A is closed after 3 mins, how much further time would it take for tap B to fill the bucket?

Answer : B

Explanation

Part of bucket filled by tap A and B together in 1 min = 1/12 + 1/15
= 3/20

∴ Part of bucket filled by A and B in 3 min = 3*3/20
= 9/20

Remaining part = 1 - 9/20
= 11/20

Tap B can fill 11/20 part in 15*11/20 = 33/4 min
= 8 min 15 sec

aptitude_pipes_cisterns.htm