Three years ago, the population of a city was $50000$. If the annual increase during three successive years is $5\mathrm{\%}$, $8\mathrm{\%}$ and $10\mathrm{\%}$ respectively, find the present population of the city.

What is the sum (in $₹$) of money which will become $₹26620$ at the rate of $10\%$ per annum at compound interest in three years?

A sum of $₹ 2500$ becomes $₹ 8100$ in $2$ years at a certain rate of compound interest. What will be the sum (in $₹$) after $4$ years?

Aminur has taken a loan of $₹64,000$ from a bank. If the rate of interest is $2.5 \mathrm{paise}$ per rupee per annum, calculate the compound interest (in $₹$) payable after $2 \mathrm{years}$.

The difference between the simple interest and the compound interest of $₹100$ in $1$ year at the rate of $10\% p.a.$ is $Re.1.$

A person deposited $₹100$ in a bank and gets the amount $₹121$ after two years. The rate of compound interest is _____ $\%.$ 

What will be the compound interest on a sum of Rs. 160000 for 2 years at the annual rate of 10%, if the interest is compounded half yearly?