Question

A 30 litre mixture of milk and water contains milk and water in the ratio 1: 2. 10 litres of the mixture is removed and replaced with pure milk and the operation is repeated once more. What is the ratio of milk and water in the resultant mixture?

• A. 17:3
• B. 3:17
• C. 9:1
• D. 19:8

Answer 1

The correct option is D 19:8

Quantities of water and milk initially = 20: 10
After first removal = 13.33: 6.67
After adding milk = 13.33: 16.67 = 4:5
Removing again $=13.33-\left(\frac{4}{9}\right)\times 10:16.67-\left(\frac{5}{9}\right)\times 10=8.89:11.11$
Adding milk again = 8.89:21.11=8:19 Required ratio is milk: water = 19:8