A cask contain 12 litres of mixture of milk and water in the ratio 3:1. How much of the mixture must be drawn off and water substituted so that milk and water in the cask may becomes half and half.

• ক 2 Litres
• খ 4 Litres ✅ সঠিক উত্তর
• গ 5 Litres
• ঘ 3 Litres