In a mixture 60 litres, the ratio of milk and water 2 : 1. If this ratio is to be 1 : 2, then the quantity of water to be further added is:

Quantity of milk =		60 x	2	litres = 40 litres.
			3

Quantity of water in it = (60- 40) litres = 20 litres.

New ratio = 1 : 2

Let quantity of water to be added further be x litres.

Then, milk : water =		40		.
		20 + x

Now,		40		=	1
		20 + x			2

 20 + x = 80

 x = 60.

 Quantity of water to be added = 60 litres.