$A$ can contains a mixture of two liquids $A$ and $B$ in the ratio $7:5$. When $9\,L$ of mixture is drained off and the can is filled with $B$,the ratio of $A$ and $B$ becomes $7:9$. How many litres of liquid $A$ was contained by the can initially?

Three bottles of equal capacity contain mixtures of milk and water in the ratios $2:5$,$3:4$,and $4:5$ respectively. These three bottles are emptied into a large bottle. What will be the ratio of milk and water respectively in the large bottle?

$A$ 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 $25 \%$?

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,minimum?

$A$ mixture of $30 \ L$ contains milk and water in the ratio of $7:3$. How much water should be added to it so that the ratio of milk and water becomes $3:7$? (in $L$)

$A$ tea seller mixes three qualities of tea $T_{1}, T_{2}$,and $T_{3}$ priced at $Rs. 74$ per kg,$Rs. 68$ per kg,and $Rs. 63$ per kg in the ratio of $1:2:4$. He added some more quantity of $T_{1}$ to $4$ kg of this mixture. He sold this new mixture for $Rs. 84$ per kg,thereby making a profit of $20\%$. How much of $T_{1}$ did he mix with the mixture? (in kg)