There are two mixtures, 'I' and 'J' of milk and water.

Solution

ATQ; Initial quantity of milk in mixture 'I' = 0.35 X 9 = 3.15 litres Initial quantity of water in mixture 'I' = 9 - 3.15 = 5.85 litres Let the quantity of milk added to the mixture be 'x' litres. Since the quantity of water in the final mixture of mixture 'I' remains the same. So, Quantity of water in the final mixture of mixture 'I' = 0.50 X (9 + x) = 5.85 Or, 9 + x = (5.85 / 0.50) Or, x = 11.7 - 9 So, x = 2.7 Quantity of milk in the resultant mixture of mixture 'I' = (3.15 + x) = 3.15 + 2.7 = 5.85 litres Initial quantity of milk in mixture 'J' = 0.25 X 21 = 5.25 litres Final quantity of milk in mixture 'J' = 5.25 + 2.7 = 7.95 litres Therefore, the quantity of milk when the final mixtures of mixture 'I' and mixture 'J' are added together = 5.85 + 7.95 = 13.8 litres