A container contains 50 litres of milk. From that 8 litres of milk was taken out and replaced by water. This process was repeated further two times. How much milk is now contained by the container?

Given that container has 50 litres of milk.

 After replacing 8 litres of milk with water for three times, milk contained in the container is:

  $\Rightarrow 501-\frac{8}{50}3$

$\Rightarrow 50\times \frac{42}{50}\times \frac{42}{50}\times \frac{42}{50}$  = 29.63 litres.