A cistern has a leak which would empty it in 15 hours. A

A cistern has a leak which would empty it in 15 hours. A tap is turned on which admits 2 litres per hour into the cistern and it is now emptied in 10 hours. How many litres does the cistern hold ?

Here w = 2 litres per hour
∴ Required answer = {(15 x 10) / (15 - 10)} x 2 = 60 litres.