$A$ man spends $75 \%$ of his income. His income increases by $20 \%$ and his expenditure also increases by $10 \%$. The percentage of increase in his savings is (in $\%$)

$6 \frac{1}{4} \%$ of $1600 + 12 \frac{1}{2} \%$ of $800$ equals

The population of a town was $160000$ three years ago. If it increased by $3 \%$,$2.5 \%$,and $5 \%$ respectively in the last three years,then the present population is:

Amit donated $20\%$ of his income to a school and deposited $20\%$ of the remainder in his bank. If he has $₹ 12800$ now,what is the income (in $₹$) of Amit?

There are $1400$ students in the school. $25 \%$ of them wear spectacles and $\frac{2}{7}$ of those who wear spectacles are boys. How many girls in the school wear spectacles?

An index of $12$ shares contains,among others,the shares of Vision Power,Vision Infra,and Vision Communication with weightage of $7\%$,$13\%$,and $15\%$ respectively. What is the increase in the prices of other shares,if these three rise by $9\%$,$10\%$,and $4\%$ respectively,while the index rises by $6\%$?