$frac{3}{4}$ part of a tank is filled with oil. After taking out 60 litres of oil the tank is $frac{2}{3}$ part full. What is the capacity (in litres) of the tank?

Let the capacity of the tank be x litres.

According to the question,

$frac{3 x}{4}-frac{2 x}{3}=60$

$Rightarrow frac{9 x-8 x}{12}=60$

$Rightarrow frac{x}{12}=60$

$Rightarrow x=12 imes 60=720 quad$ litres