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 - 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

Answer : B

Explanation

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 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:

A - 7/3 hours

B - 7 hours

C - 8 hours

D - 14 hours

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 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 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

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 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 - 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

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 - If two funnels work at the same time, the repository will be filled in 12 hours. One channel fills the store 10 hours quicker than the request. How long does the speedier funnel take to fill the store?

A - 25 hours

B - 28 hours

C - 30 hours

D - 35 hours

Answer : C

Explanation

Suppose that one pipe takes x hours to fill the reservoir.
Than the other pipes takes (x-10) hours.
∴ 1/x+ 1/(x-10) = 1/12 ⇒12(x-10+x)= x(x-10)
⇒x2-34x +120=0 ⇒(x-30) (X-4) =0
⇒x= 30 or x= 4
So, the faster pipe takes 30 hrs to fill the reservoir.

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 - 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 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?

A - 8 min 5 sec

B - 8 min 15 sec

C - 7 min 45 sec

D - 7 min 15 sec

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
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