# Aptitude - Pipes and Cistern - Discussion

Discussion Forum : Pipes and Cistern - General Questions (Q.No. 2)
2.
Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in:
 1 13 hours 17
 2 8 hours 11
 3 9 hours 17
 4 1 hours 2
Explanation:

 Net part filled in 1 hour 1 + 1 - 1 = 17 . 5 6 12 60

 The tank will be full in 60 hours i.e., 3 9 hours. 17 17

Discussion:
56 comments Page 1 of 6.

First take a, b, c = 5, 6, 12.
Take a lcm of a, b, c = 60.
And divide by 5/60, 6/60, 12/60.

We get the answer of 12, 10,-5 because c can empty the tank it takes it as a negative term.
12 + 10 - 5 = 17.
Then divide by 60/17.
We get 3.58.

(1)

Sanjiv said:   2 years ago
Superb explanation. Thanks @Manasa.
(3)

Akshay kenjila said:   3 years ago
@Manasa.

Soperb explainations. Thank you.

Naren said:   3 years ago
Thanks for explaining @Manasa.

BISWANATH TRIPATHY said:   3 years ago
How it is possible? Explain, please.
(1)

Marion said:   3 years ago
How does 60/17 become 39/17? Explain me.

Sireeshadevi koppisetti said:   4 years ago
Thanks @Subrat Kumar Dhani.

Rupa said:   5 years ago
@Sekhar.

17*3+9/60 = 60/17.

Lavanya said:   5 years ago
Thanks all.

Ragavi said:   5 years ago
How to calculate it when the time is in minutes (intsead of hrs)? Please tell me.
(1)