-
Pipe A and B can fill a tank in 12 and 15 hours respectively. An outlet pipe C, can empty it in 6 hours. Initially pipes A and B are opened together, and after 5 hours pipe C is also opened. Find the time required to empty the tank?
-
- 45 hours
- 50 hours
- 60 hours
- None of these
- 45 hours
Correct Option: A
As per the given in question , we have
| Tank filled by A & B in 5 hours = 5 |  | + |  | = | = | ||||
| 12 | 15 | 60 | 4 |
| Work done in 1 hour when all 3 pipes are opened = | + | - | = | = | |||||
| 12 | 15 | 6 | 60 | 60 |
Since the result (or net effect) is negative, hence tank would be emptied.
| So, 1/60 is emptied in 1 hour 3/4 would be emptied in | × | = 45 hours | ||
| 1/60 | 4 |
