question_answer

Two pipes can fill a cistern in 12 hours and 15 hours respectively. Due to leakage in the bottom, 30 minutes extra are taken for the cistern to be filled up if both the pipes are open together. If the cistern is full, how much time will the leak take to empty the tank?

A)  97.5 hours

B)  95.5 hours

C)  93.5 hours

D)  91.5 hours

E)  None of these