### 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:

A. 81 litres B. 71 litres C. 56 litres D. 50 litres Answer: Option A

### Solution(By Apex Team)

Quantity of milk in 729 litre of mixture = 7 × $\Large\frac{729}{9}$ = 567 litre Quantity of water = 729 – 567 = 162 litres Let x litre of water be added to become ratio 7 : 3 $\begin{array}{l}\text{ Or, }\Large\frac{7}{3}=\frac{567}{162+\mathrm{x}}\\ \text{ Or, }162\times7+7x=567\times3\\ \text{ Or, }7x=1701-1134=567\\ \text{ Or, }\mathrm{x}=\Large\frac{567}{7}\\ \therefore\ x=81\end{array}$

## Related Questions On Alligation

A. 2 : 5
B. 3 : 5
C. 5 : 3
D. 5 : 2

### An alloy contains zinc, copper and tin in the ratio 2 : 3 : 1 and another contains copper, tin and lead in the ratio 5 : 4 : 3. If equal weights of both alloys are melted together to form a third alloy, then the weight of lead per kg in new alloy will be:

A. $\large\frac{1}{2} \mathrm{~kg}$
B. $\large\frac{1}{8} \mathrm{~kg}$
C. $\large\frac{3}{14} \mathrm{~kg}$
D. $\large\frac{7}{9} \mathrm{~kg}$

A. 81 litres
B. 71 litres
C. 56 litres
D. 50 litres