In mixture A of 180 litres, the ratio of milk and water is 5 : 1. If this ratio is to be 3 : 2, then find the quantity of water to be added further.

70 l 

The original ratio of milk and water = 5 : 1

Total quantity = 180l 

Milk = $\frac{5}{6}$ x 180 = 150

Water = $\frac{1}{6}$ x 180 = 30

The quantity of milk remains same, while 'x'l of water is added to make the ratio 3 : 2

If $\frac{3}{5}$ of (180+ x) = 150

⇒ 3(180 + x) = 150 x 5

⇒ 540 + 3x = 750

⇒      3x = 210   or x = 70

Thus, 70l of water was added to obtain the new ratio.