Suppose initial quantity of milk & water in the mixture are 5x & 4x, then 2 litres water is added. Hence, New quantity of milk & water will be 5x & (4x + 2) ATQ, 5x/(4x + 2) = 10/9 x/(4x + 2) = 2/9 9x = 8x + 4 x = 4 Hence, new amount of water in the mixture = 4x + 2 = (4×4) + 2 = 18 litres