Pipe and Cistern

Two pipes A and B can fill an empty tank in 10 and 15 hours respectively. Hari opens these two pipes simultaneously. After 2 hours he comes back and finds that there is a leak in the tank. He stops the leakage and thus tank took 6 hours more to be filled completely after closing the leak. In what time leakage will empty full tank?
(A) 6 hours

(B) 9 hours

(C) 8 hours

A tank has two pipes P and Q that can fill it in 12 hours and 18 hours respectively. There is also a waste pipe R attached to the tank. When all the three pipes are opened together, the empty tank is full in 11 1/4 hours. How long will the waste pipe take to empty the full tank? (in minutes)

(A) 20

(B) 22

(C) 24

(D) None of these

A tank can be filled by a pipe A in 30 minutes and by another pipe B in 20 minutes. S opened both the pipes and leaves and returns at the time when the tank should be full. He observed that there is a leakage at the bottom, he now closes it. Now the tank will take more 10 minutes to fill the tank, find the time in which the leak can empty the tank.

[A] 72 min

[B] 60 min

[C] 36 min

[D] None of these

A pipe can fill a tank in 30 minutes but due to a leak developed at the bottom of the tank, 1/4 of the water filled by the pipe leaks out. Find the time in which the tank is filled.

[A] 25 min

[B] 36 min

[C] 40 min

[D] None of these