Question

two pipes A and B can separately fill cistern in 20 minutes and 30 minutes respectively, while a third pipe c can empty the full cistern in 15 minutes . If all the pipes are opened together, in what the empty cistern is filled?

Answer 1

Heyaa!!here is the answer

60minuits

Step-by-step explanation:

Pipe A can fill the cistern = 20 minutes

So, In 1 minute the fraction of cistern filled by pipe A =

Pipe B can fill the cistern = 30 minutes

So, In 1 minute the fraction of cistern filled by pipe B =

Pipe C can empty the full cistern = 15 minutes

So, In 1 minute the fraction of cistern emptied by pipe C =

Therefore,

In 1 minute, the fraction of cistern filled, if all the 3 pipes are opened together is,

Thus, if all the 3 pipes are opened together, then the empty cistern is filled in 60 minutes.