What is the simple interest (in ₹) on ₹ $5400$ in $5$ years at the rate of $12 \%$ per annum?

If a certain sum of money borrowed at $5 \%$ per annum simple interest amounts to ₹ $1020$ in $4$ years,then the sum of money (in ₹) borrowed is:

If ₹ $1000$ is invested at an interest rate of $5 \%$ and the interest is added to the principal every $10$ years,then the number of years in which it will amount to ₹ $2000$ is:

$A$ sum of money invested at $S.I.$ accrued to $Rs. 800$ in $3$ years and to $Rs. 840$ in $4$ years. The rate of interest (in $\%$) per annum is:

$A$ sum of $Rs. 15000$ amounts to an interest of $Rs. 4500$ in $5$ years. What is the rate of interest (in percentage)?

If the annual rate of simple interest increases from $10 \%$ to $12 \frac{1}{2} \%$,a man's yearly income increases by ₹ $1250$. His principal (in ₹) is