If the given two numbers are respectively $7 \%$ and $28 \%$ of a third number,then what percentage is the first of the second?

$23 \%$ of $8040 + 42 \%$ of $545 = ? \%$ of $3000$

$A$ number is increased by $84$,it becomes $107 \%$ of itself. What is the number?

The population of a town increased from $1,75,000$ to $2,62,500$ in a decade. The average percent increase of population per year is?

An ore contains $23 \%$ copper. To get $69 \text{ kg}$ of copper, the quantity of the ore required is: (in $\text{ kg}$)

Rama's expenditure and savings are in the ratio $3:2$. His income increases by $10\%$. His expenditure also increases by $12\%$. His savings increases by: (in $\%$)