The population of a town $2$ years ago was $62500$. Due to migration to big cities,it decreases every year at the rate of $4\%$. The present population of the town is:

If the income of $R$ is $30 \%$ more than the income of $Q$ and the income of $Q$ is $20 \%$ more than the income of $P$,then the income of $R$ is how much percent more than the income of $P$ (in $\%$)?

If $A$'s income is $25 \%$ less than that of $B$,then how much per cent is $B$'s income more than that of $A$?

Ram donated $4 \%$ of his income to a charity and deposited $10 \%$ of the rest in a bank. If now he has $Rs$ $8640$ left with him,then his income is

$A$ student multiplied a number by $\frac{3}{5}$ instead of $\frac{5}{3}$. What is the percentage error in the calculation (in $\%$)?

$\frac{3}{4}$ of $\frac{2}{3}$ of $\frac{1}{5}$ of a number is $249.6$. What is $50\%$ of that number?