The ratio of milk to water is 5:4. If two litres of water is added, the ratio becomes 10:9, then find the new amount of water in the mixture.

Let initial quantity of milk & water in the mixture are 5x & 4x
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.