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?

What percent of Rs. $2650$ is Rs. $1987.50$?

If $A$'s salary is $40\%$ less than that of $B$,then how much percent is $B$'s salary more than that of $A$?

In a certain school,$20 \%$ of students are below $8$ years of age. The number of students above $8$ years of age is $2/3$ of the number of students of $8$ years of age,which is $48$. What is the total number of students in the school?

How many litres of pure acid are there in $8$ litres of a $20\%$ solution?

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 $6\%$?