Question

Two pipes A and B can separately fill a cistern in 20 and 30 minutes respectively while a third pipe can empty it in 15 minutes .if all the pipes are opened simultaneously in how much time will the cistern be filled

Answer 1

Answer:

60minutes

Step-by-step explanation:

In 1munite

Pipe A can fill 1/20

Pipe B can fill 1/30

Pipe C can empty in 1/15

All together it will be

1/20+1/30-1/15=1/60

It will take 60minutes