The ratio of milk and water in mixtures of four containers are $5:3$,$2:1$,$3:2$,and $7:4$,respectively. In which container is the quantity of milk,relative to water,the minimum?

Acid and water are mixed in a vessel $A$ in the ratio of $5:2$ and in the vessel $B$ in the ratio $8:5$. In what proportion should quantities be taken out from the two vessels so as to form a mixture in which the acid and water will be in the ratio of $9:4$?

Two vessels contain milk and water in the ratio $3:2$ and $7:3$. Find the ratio in which the contents of the two vessels have to be mixed to get a new mixture in which the ratio of milk and water is $2:1$.

$A$ $12 \text{ litres}$ cylinder contains a mixture of oxygen and nitrogen,the volume of oxygen being $40 \%$ of the total volume. $A$ few litres of the mixture is released and an equal amount of nitrogen is added. Then,the same amount of the mixture as before is released and replaced by nitrogen for the $second$ time. As a result,the oxygen content becomes $10 \%$ of the total volume. How many $litres$ of the mixture is released each time?

$A$ tub contains a mixture of two liquids $P$ and $Q$ in the ratio of $4:1$. When $10 \, L$ of the mixture is taken out and $10 \, L$ of liquid $Q$ is poured into the tub,the ratio becomes $2:3$. How many litres of liquid $P$ were contained in the tub initially?

$A$ merchant has $1000 \ kg$ of rice,part of which he sells at $8 \%$ profit and the rest at $16 \%$ profit. He gains $14 \%$ on the whole. The quantity sold at $16 \%$ profit is (in $kg$):