$A$ sum of ₹ $15000$ deposited at compound interest becomes double after $5$ $years$. After $20$ $years$,it will become (in ₹):

The difference between the simple interest on a certain sum at the rate of $10 \%$ per annum for $2$ years and compound interest which is compounded every $6$ months is ₹ $124.05$. What is the principal (in ₹)?

$A$ sum of money at compound interest amounts in two years to Rs. $2809,$ and in three years to Rs. $2977.54.$ Find the rate of interest and the original sum.

$A$ tree increases annually by $\frac{1}{8}$ of its height. By how much will it increase (in $cm$) after $2$ years,if it stands today $64 \ cm$ high?

$A$ man borrows ₹ $3825$ to be paid back with compound interest at the rate of $4 \%$ per annum by the end of $2$ years in two equal yearly instalments. How much will be each instalment (in ₹)?

The simple interest accrued on a certain principal is ₹ $2,000$ in five years at the rate of $4$ percent $p.a.$ What would be the compound interest (in ₹) accrued on the same principal at the same rate in two years?