A 20 litre mixture contains milk and water in the respective ratio of 3:2. If 10 litre of the mixture is removed and replaced with pure milk and the operation is repeated once more. At the end of the two removals and replacement, what is the ratio of milk and water in the resultant mixture respectively

Amount of water in the mixture

= 20×2/5=8 litre

Amount of milk in the mixture = 20-8 = 12 litre

We know that,

W^r/W₀=[1-R/M]ⁿ

Here Wr= Amount of water in the mixture after the replacements have taken place.

W₀= Amount of water in the mixture

W^r/W₀=[1-10/20]²=[1-I/2]²

W^r/W₀=[1/2]²=1/4

W^r=8/4=2 litre

Hence, the mixture will have 18 litre of milk and 2 litre of water.

∴ Required ratio = 18:2 = 9:1