The population of Delhi two years ago was $55000$. It increased by $12 \%$ in the first year and decreased by $15 \%$ in the second year. What was the population of the town at the end of $2$ years?

If the height of a triangle is decreased by $40 \%$ and its base is increased by $40 \%$,what will be the effect on its area?

The salary of a person was reduced by $10 \%$. By what percent should his reduced salary be raised so as to bring it at par with his original salary (in $\%$)?

Mr. Giridhar spends $50 \%$ of his monthly income on household items. Out of the remaining,he spends $50 \%$ on transport,$25 \%$ on entertainment,and $10 \%$ on sports. If the remaining amount of $RS. 900$ is saved,what is Mr. Giridhar's monthly income?

If the numerator of a fraction is increased by $150 \%$ and the denominator of the fraction is increased by $350 \%,$ the resultant fraction is $\frac{25}{51},$ what is the original fraction?

The price of an article is Rs. $100$. Its price is increased by $10 \%$,and then again its price is increased by $10 \%$. What is the total increase in the price?