In what ratio must a grocer mix two varieties of tea worth $Rs. 60$ per $kg$ and $Rs. 65$ per $kg$ so that by selling the mixture at $Rs. 68.20$ per $kg$ he may gain $10\%$?

$A$ person has a chemical of ₹ $25$ per litre. In what ratio should water be mixed in that chemical,so that after selling the mixture at ₹ $20$ per litre,he may get a profit of $25 \%$?

$A$ can contains a mixture of two liquids $A$ and $B$ in the ratio $7:5$. When $9$ litres of the mixture are drawn off and the can is filled with $B$,the ratio of $A$ and $B$ becomes $7:9$. The quantity of liquid $A$ contained by the can initially was:

$A$ mixture contains $80 \%$ acid and the rest water. The part of the mixture that should be removed and replaced by the same amount of water to make the ratio of acid and water $4:3$ is

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 $9:4$?

$A$ mixture of a certain quantity of milk with $16$ litres of water is worth $90$ $P$ per litre. If pure milk is worth $Rs. 1.08$ per litre,how much milk is there in the mixture? (in Litres)