The acid and water in two vessels $A$ and $B$ are in the ratio $4:3$ and $2:3$. In what ratio should the liquids in both the vessels be mixed to obtain a new mixture in vessel $C$ containing half acid and half water?

$A$ shopkeeper bought $30 \text{ kg}$ of rice at the rate of $₹ 70$ per $\text{kg}$ and $20 \text{ kg}$ of rice at the rate of $₹ 70.75$ per $\text{kg}$. If he mixed the two brands of rice and sold the mixture at $₹ 80.50$ per $\text{kg}$,his total gain is (in $₹$):

$49 \ kg$ of blended tea contains Assam and Darjeeling tea in the ratio $5:2$. The quantity of Darjeeling tea to be added to the mixture to make the ratio of Assam to Darjeeling tea $2:1$ is..........$kg$.

$A$ $20\, \text{litre}$ mixture of milk and water contains milk and water in the ratio $3:2$. $10\, \text{litres}$ of the mixture is removed and replaced with pure milk,and the operation is repeated once more. At the end of the two removals and replacements,what is the ratio of milk and water in the resultant mixture?

In a mixture of $75 \ L$,the ratio of milk to water is $2:1$. The amount of water to be further added to the mixture so as to make the ratio of the milk to water $1:2$ will be (in $L$):

$A$ merchant has $1000 \ kg$ of sugar,part of which he sells at $8 \%$ profit and the rest at $18 \%$ profit. If he gains $14 \%$ on the whole,then the quantity sold at $18 \%$ profit is.......$kg$.