$8$ litres of water is added to $32$ litres of a solution containing $20 \%$ of alcohol in water. What is the approximate concentration of alcohol in the solution now? (in $\%$)

$A$ 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?

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

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?

$A$ dishonest trader professes to sell his article at cost price but he uses $900 \, g$ weight instead of $1 \, kg$. What is the percentage gain of the trader in this trade?

$300$ $gm$ of sugar solution contains $40 \%$ sugar. How much sugar (in $gm$) should be added to make the concentration $50 \%$ in the solution?