Question

A bath can be filled by the cold water pipe in 10 min and by the hot water pipe in 15 min. A person leaves the bath room after turning on both pipes simultaneously and returns at the moment when the bath should be full. Finding, however, that the waste pipe has been open, he now closes it. In 4 minutes more the bath is full. In what time would the waste pipe empty it?

Answer 1

Answer:

7.5

Step-by-step explanation:

cold water pipe complete in=10min=1/10

hot water pipe complete in=15min=1/15

subtracting(1)and(2)we get

both them do in 4min=1/10-1/15=1/30

both of them do in 4min=1/30×4=7.5