Question

the petrol tank of a truck is one quater full the driver adds 70liters of petrol to tank. the tank is one half full now. how many liters of petrol can the full tank hold

Answer 1

let total capacity be a
at first,The petrol tank of a truck is one quater full
this is nothing but 1/4a

when the driver adds 70liters of petrol to tank, it is 1/2a
=1/4a+70=1/2a
=1/4a-1/2a=70
=1/2a=70
a=70*2
a=140 litres