Question

A water pipe can fill a 250 litre tank in 2 hours 30 minutes. in how much time will it fill 9/10 of the tank.

Answer 1

A.T.Q
the pipe take 2 hrs 30 mins(150 minutes)to fill 250 liters tanks
that means to fill 1 litre it will take 150/250 minutes.
9/10 of the tank(250 litre) =9/10*250=225.
If,it take 150/250 minutes to fill one litre of tank,so the time taken to fill  225 litres =(Time taken to fill 1 litre)*(Number of litre)
=150/250*225 minutes
=135 minutes (2 hours 15 minutes).