Pipe a can fill a tank in X hours. Pipe B can empty it in 15 both the pipes are opened together, then the tank will be filled in 7 hours and 30 minutes. Find X.

Correct option is B

Given,
· Pipe A fills the tank in X hours.
· Pipe B empties the tank in 15 hours.
· When both pipes are open together, the tank is filled in 7 hours and 30 minutes = 7.5 hours.
Steps:
Filling Rates:
· Pipe A's rate: 1/X tank/hour.
· Pipe B's rate: -1/15 tank/hour (negative because it empties).
Combined Rate: When both pipes are open, the combined rate is: