Question

Sol. (1) Quantity of milk in 729 litres of mixture
( =frac{7}{9} times 729=567 ) litres
Quantity of water ( =(729-567) ) litres ( =162 ) litre. Let ( x ) litres of water is mixed to get the required ratio of 7: 3
( therefore frac{567}{162+x}=frac{7}{3} )
( Rightarrow 7 x+1134=1701 )
( Rightarrow 7 x=1701-1134=567 )
( Rightarrow x=frac{567}{7}=81 ) litres

# Ex. 1. In a 729 litres mixture of milk and water, the ratio of milk to water is 7:2. To get a new mix- ture containing milk and water in the ratio 7: 3, the amount of water to be added is (1) 81 litres (2) 71 litres (3) 56 litres (4) 50 litres

Solution