The simple interest accrued on an amount of ₹ $22,500$ at the end of four years is ₹ $10,800$. What would be the compound interest accrued on the same amount (in ₹) at the same rate of interest at the end of two years?

If the interest on ₹ $800$ is more than the interest on ₹ $400$ by ₹ $40$ in $2$ years,then the rate of interest (in $\%$) per annum is:

$A$ certain sum becomes $5$ times in $3$ years at simple interest. In how many years will it become $13$ times?

The simple interest on a sum of money will be ₹ $600$ after $10$ $years$. If the principal is trebled after $5$ $years$,then what will be the total interest (in ₹) at the end of the tenth year?

The rate of interest on a sum of money is $4 \%$ per annum for the first $2$ years,$6 \%$ p.a. for the next $4$ years,and $8 \%$ p.a. for the period beyond $6$ years. If the simple interest accrued by the sum for a total period of $9$ years is ₹ $1120$,then the sum (in ₹) is:

$A$ person invested $\frac{2}{3}$ of his capital at $3 \%$,$\frac{1}{6}$ at $6 \%$,and the remainder at $12 \%$. If his annual income is $₹ 25$,then the total capital (in $₹$) is: