A certain sum at compound interest amounts in two years to ₹ $2809$ and in three years to ₹ $2977.54 .$ Find the rate of interest and the original sum (In ₹).

The difference between simple interest and compound interest (In ₹) on ₹ $1250$ for $2$ years at $4 \%$ $p.a.$ is

Mr. Dua invested money in two schemes $A$ and $B$ offering compound interest at $8 \%$ per annum and $9 \%$ per annum respectively. If the total amount of ineterest accrued through two schemes together in two years was ₹ $4818.30$ and the total amount invested was ₹ $27000$ . What was the amount (In ₹) invested in scheme $A$.

On a certain principal if the simple interest for two years is ₹ $1400$ and compound interest for the two years is ₹ $1449,$ what is the rate of interest (In $\%$) ?

A person takes ₹ $10,000$ loan at the rate of $10 \%$ interest compounding yearly for the period of $4$ years. How much interest (In ₹) he has to pay?

The population of a town increases by $5 \%$ every year. If the present population is $9261,$ the population $3$ $years$ ago was