$A$ person's salary has increased from $Rs. 7200$ to $Rs. 8100$. What is the percentage increase in his salary (in $\%$)?

If $A$ is $150 \%$ of $B$,then $B$ is what percent of $A+B$?

In an office,$40 \%$ of the staff is female,$70 \%$ of the female staff and $50 \%$ of the male staff are married. The percentage of the unmarried staff in the office is

$25 \%$ of $25 \% = ?$

In a hotel,$60 \%$ of people had vegetarian lunch,$30 \%$ had non-vegetarian lunch,and $15 \%$ had both types of lunch. If $96$ people were present,how many did not have either type of lunch?

The difference between two numbers is $1600$. If $7.5\%$ of one number is equal to $12.5\%$ of the other number,find the two numbers.