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 1 of 2.
Rohit said:
1 decade ago
How to solve x+6+x/x(x+6)-1/4. to form equation. Please tell me the steps..
Shivam said:
1 decade ago
4(2x+6) = x2+6x
0=-24-2x+x2
x2-2x-24 = 0
(x-6)(x+4) = 0
x=6 or x =-4
0=-24-2x+x2
x2-2x-24 = 0
(x-6)(x+4) = 0
x=6 or x =-4
(1)
RashmiBs said:
1 decade ago
A+B's 1 hours work = 1/4.
B's 1 hours work = 1/6.
First let us find out the B's Part = (1/6)-(1/4).
This is actual B's part of work = 1/12.
Now, find actual A's part = new value of B-(A+B).
= (1/12) - (1/4).
= 2/12 = 1/6 = 6 Hours.
B's 1 hours work = 1/6.
First let us find out the B's Part = (1/6)-(1/4).
This is actual B's part of work = 1/12.
Now, find actual A's part = new value of B-(A+B).
= (1/12) - (1/4).
= 2/12 = 1/6 = 6 Hours.
(8)
Aman said:
1 decade ago
Why we reciprocal the equation?
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.
Nirmala Devi said:
9 years ago
How x + 6? Explain.
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.
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.
Kishan said:
9 years ago
Good explanation @Rashmibs.
Neha said:
9 years ago
Please explain it.
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