In a 729 litres mixture of milk and water, the ratio of

In a 729 litres mixture of milk and water, the ratio of milk to water is 7 : 2. To get a new mixture containing milk and water in the ratio 7 : 3, the amount of water to be added is

Quantity of milk in 729 litres of mixture

=	7	× 729 = 567 litres
	9

∴ Quantity of water
= (729 – 567) litres = 162 litres.
Let x litres of water is mixed to get the required ratio of 7 : 3

∴	567	=	7
	162 + x		3

⇒ 7x + 1134 = 1701
⇒ 7x = 1701 – 1134 = 567

⇒ x =	567	= 81 litres
	7