Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 5)
5.
A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is:
Answer: Option
Explanation:
Suppose, first pipe alone takes x hours to fill the tank .
Then, second and third pipes will take (x -5) and (x - 9) hours respectively to fill the tank.
 |
1 | + | 1 | = | 1 |
| x | (x - 5) | (x - 9) |
 |
x - 5 + x | = | 1 |
| x(x - 5) | (x - 9) |
(2x - 5)(x - 9) = x(x - 5)
x2 - 18x + 45 = 0
(x - 15)(x - 3) = 0
x = 15. [neglecting x = 3]
Discussion:
68 comments Page 6 of 7.
SABYASACHI said:
1 decade ago
Is there any short tricks for this type of questions?
Inu said:
1 decade ago
Time cannot be negative. Thats why 3 is neglected.
Rekha said:
1 year ago
Why it is 1 as a numerator? Please explain to me.
(4)
Debasish said:
9 years ago
Is there any shortcut method for solving it?
Deepak Pareek said:
1 decade ago
Solve through options. It will be easier.
Virajgouda said:
9 years ago
Why do you neglect 3? What is the reason?
Yogi said:
3 years ago
Thanks a lot for your explanation @Nita.
(4)
Karthikeyan said:
1 decade ago
How got this equation 1/x+1/x-5=1/x-9 ?
(1)
Amol Phad said:
10 years ago
Please somebody tell me in easier way.
Pranesh kumar said:
1 decade ago
Why you neglect x=3 for what reasons?
(1)
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