Vishwanath
Wednesday, February 20, 2013
15. | Two pipes A and B can fill a cistern in 37 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the B is turned off after:
|
A. | 5 min. | B. | 9 min. | C. | 10 min. | D. | 15 min. |
|
Answer: Option B
Explanation:
Let B be turned off after x minutes. Then,
Part filled by (A + B) in x min. + Part filled by A in (30 -x) min. = 1.
x |
| 2 | + | 1 |
| + (30 - x). | 2 | = 1 |
75 | 45 | 75 |
11x + 180 - 6x = 225.
x = 9.
Title : Pipes And Cisterns Q15
Description : 15. Two pipes A and B can fill a cistern in 37 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in jus...
Rating : 5
