Two pipes A and B can separately fill a cistern in 150 minutes and 120 minutes respectively. There is a third pipe in the bottom of the cistern to empty it. If all the three pipes are simultaneously opened, then the cistern is full in 100 minutes. In how much time, the third pipe alone can empty the cistern ?
Solution: Work done by third pipe in 1 min. = (1/150 + 1/120) - 1/100
= 3/200 - 1/100
.'.The third pipe alone can empty the cistern in 200 min.
Back To Top