Question

Two pipes A and B can separately fill a cistern in 10
minutes and 15 minutes respectively. A person opened
both the pipes together to fill the tank but found after
the due time that the exhaust pipe was open and the tank could hence. not be filled .so he closed the exhaust pipe.then after another b4 minutes the tank became full.in what time will the exhaust pipe empty the full tank?​

Answer 1

Answer:

60 minutes will fill tank after