Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 8)
8.
Two pipes A and B together can fill a cistern in 4 hours. Had they been opened separately, then B would have taken 6 hours more than A to fill the cistern. How much time will be taken by A to fill the cistern separately?
Answer: Option
Explanation:
Let the cistern be filled by pipe A alone in x hours.
Then, pipe B will fill it in (x + 6) hours.
 |
1 | + | 1 | = | 1 |
| x | (x + 6) | 4 |
 |
x + 6 + x | = | 1 |
| x(x + 6) | 4 |
x2 - 2x - 24 = 0
(x -6)(x + 4) = 0
x = 6. [neglecting the negative value of x]
Discussion:
18 comments Page 2 of 2.
Ajay said:
8 years ago
How x2-2x-24= (x-6) (x+4)? Please explain.
Neha said:
9 years ago
Please explain it.
Kishan said:
9 years ago
Good explanation @Rashmibs.
Achal Kalpande said:
9 years ago
A x x+6 u/m.
B x+6 x u/m.
LCM = x(x + 6).
x(x + 6)/(x + 3) = 8.
Now put values in options in x.
When both sides equate, we get x = 6.
B x+6 x u/m.
LCM = x(x + 6).
x(x + 6)/(x + 3) = 8.
Now put values in options in x.
When both sides equate, we get x = 6.
Anshul said:
9 years ago
Pipe B takes 6 hours more than Pipe A to fill the same tank so x+6 for pipe B.
Nirmala Devi said:
9 years ago
How x + 6? Explain.
ABDULLAH said:
9 years ago
@Aman.
Because we have to obtain work done in one hour and we have to find the total time to complete a full work by A or B.
Because we have to obtain work done in one hour and we have to find the total time to complete a full work by A or B.
Aman said:
1 decade ago
Why we reciprocal the equation?
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