A 24 litres of milk and water mixture contains milk and water in the ratio 3 5 What litres of the mi...........

Explanation:

In 24 l of mixture, milk = 3/8 * 24 = 9 l, so water = 15 l
Now since the mixture is to be replaced with pure milk, the amount of mixture will remain same after replacement too.
In 24 l mixture, to have 12 l water and 12 l milk, 3 l of water should be taken out, since we are only adding milk.
Let x l of mixture taken out. So 5/8 * x = 3,
Solve, x = 24/5 l

Hence, option 4 is the correct answer.