$x \%$ of $y + y \%$ of $x = ?$

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?

Aditya has some amount,out of which $25 \%$ is stolen,$10 \%$ he gave to his friend,$50 \%$ of the remainder is spent on a party,and the rest $Rs. 26$ he gave to his mother. What was his initial amount?

The population of a city is $20000$. It increased by $20\%$ during the first year and $30\%$ during the second year. The population after two years will be:

In an examination,$34 \%$ of students failed in Mathematics and $42 \%$ failed in English. If $20 \%$ of the students failed in both the subjects,then the percentage of students who passed in both the subjects was: