Ravi is $12$ years younger than Surya. Ravi's age is $40 \%$ of the sum of his and Surya's age. What will be Surya's age $9$ years hence?

The population of a town increases $4 \%$ annually but is decreased by emigration annually to the extent of $(1/2) \%$. What will be the increase per cent in $3$ years?

An army lost $10 \%$ of its men in war,$10 \%$ of the remaining died due to disease,and $10 \%$ of the rest were declared disabled. Thus,the strength of the army was reduced to $7,29,000$ active men. What was the original strength of the army?

Sunil decided to donate $5 \%$ of his salary. On the day of donation,he changed his mind and donated $₹ 1687.50$,which was $75 \%$ of what he had decided earlier. How much is Sunil's salary?

Harjeet spends $50 \%$ of his monthly income on household items,$20 \%$ of his monthly income on buying clothes,$5 \%$ of his monthly income on medicines and the remaining amount of $Rs. 11250$ he saves. What is Harjeet's monthly income?

$A$ man spends $75 \%$ of his income. His income is increased by $20 \%$ and he increases his expenditure by $10 \%$. His savings are increased by: (in $\%$)