Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 14)
14.
Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in:
Answer: Option
Explanation:
| (A + B)'s 1 hour's work = |  |
1 | + | 1 |  |
= | 9 | = | 3 | . |
| 12 | 15 | 60 | 20 |
| (A + C)'s hour's work = | |
1 | + | 1 | |
= | 8 | = | 2 | . |
| 12 | 20 | 60 | 15 |
| Part filled in 2 hrs = | |
3 | + | 2 | |
= | 17 | . |
| 20 | 15 | 60 |
| Part filled in 6 hrs = | |
3 x | 17 | |
= | 17 | . |
| 60 | 20 |
| Remaining part = | |
1 - | 17 | |
= | 3 | . |
| 20 | 20 |
| Now, it is the turn of A and B and | 3 | part is filled by A and B in 1 hour. |
| 20 |
Total time taken to fill the tank = (6 + 1) hrs = 7 hrs.
Discussion:
52 comments Page 4 of 6.
Paridhi said:
1 decade ago
It written part filled in six hours then why is it multiplied by 3 and not six?
INNA REDDY CHILAKALA said:
9 years ago
@Anil.
Your method is simple and easy to solve the solution.
Thank you.
Your method is simple and easy to solve the solution.
Thank you.
Gnanamayil.k said:
1 decade ago
I feel its all lengthy calculation. Is there any simple shortcut method?
Swetha said:
10 years ago
Please say short cut method for problem 14 it is length process.
Saitriveni said:
1 decade ago
How come you consider 6 hrs duration for the part fillings?
Siva said:
9 years ago
Thank you, @Alvin.
Your method is easy and really simple.
Your method is easy and really simple.
Ashish said:
3 years ago
How to solve this by lcm method? Please explain me.
(3)
M.V.KRISHNA said:
1 decade ago
Why 6hrs are taken, I think question is not clear.
Brajesh said:
9 years ago
It was a nice solution @Alvin .
Thank you.
Thank you.
Sadam said:
9 years ago
x/12 + (1/15 + 1/20) x/2 = 1.
x = 7 hours.
x = 7 hours.
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