Explanation:

- Start with a 64-litre mixture of milk and water with a 15:1 ratio.

- Calculate the amount of milk: \((15/16) \times 64 = 60\) litres.

- Calculate the amount of water: \(64 - 60 = 4\) litres.

- 24 litres of the mixture is removed. Use the same ratio (15:1) for removal.

- Milk removed: \((15/16) \times 24 = 22.5\) litres.

- Water removed: \(24 - 22.5 = 1.5\) litres.

- Remaining milk: \(60 - 22.5 = 37.5\) litres.

- Remaining water: \(4 - 1.5 = 2.5\) litres.

- Add 5 litres each of milk and water.

- Final amount of milk: \(37.5 + 5 = 42.5\) litres.

- Final amount of water: \(2.5 + 5 = 7.5\) litres.

- Difference between milk and water: \(42.5 - 7.5 = 35\) litres.

Option 3: 35 litres

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