Question

A 20 litre mixture contains milk and water in the respective ratio of 3 : 2. Then 10 litres 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 replacements, what is the ratio of milk and water in the resultant mixture respectively?

Options

• 17 : 3

• 9 : 1

• 4 : 17

• 5 : 3

Answer 1

9 : 1

Explanation:

In 20 litres of mixture

Milk = `3/5 xx 20` = 12 litres

Water = 8 litres

In 10 litres of mixture,

Milk = 6 litres

Water = 4 litres

On adding 10 litres of milk,

Milk ⇒ 12 – 6 + 10 = 16 litres

Water ⇒ 8 – 4 = 4 litres

Again in 10 litres of mixture, 

Milk = `4/5 xx 10` = 8 litres

Water = 2 litres

On adding 10 litres of milk,

Milk = 16 – 8 + 10 = 18 litres

Water = 2 litres

Required ratio = 18 : 2 = 9 : 1