Pipe P can fill a tank in 38 hours. Pipe Q alone can fill it in 19 hours. Pipe R can empty the full tank in 133 hours. If all the pipes are opened together, how much time will be needed to make the tank full?

| Question | Pipe P can fill a tank in 38 hours. Pipe Q alone can fill it in 19 hours. Pipe R can empty the full tank in 133 hours. If all the pipes are opened together, how much time will be needed to make the tank full? | |
| Type | multiple_choice | |
| Option | 28 hours | incorrect |
| Option | 95 hours | incorrect |
| Option | 19 hours | incorrect |
| Option | 14 hours | correct |
Solution