The difference between simple and compound interest on a sum of $10000$ is $64$ for $2$ years. Find the rate of interest. (in $\%$)

The simple interest accrued on an amount of $Rs. 20000$ at the end of $3$ years is $Rs. 7200$. What would be the compound interest accrued on the same amount at the same rate in the same period?

The simple interest accrued on an amount of $Rs. 19800$ at the end of $3$ years is $Rs. 7128$. What would be the compound interest (in $Rs.$) accrued on the same amount at the same rate in the same period?

The difference between simple interest and compound interest compounded annually on a certain sum of money for $2$ years at $4 \%$ per annum is ₹ $1$. The sum (in ₹) is

The difference between the $S.I.$ and $C.I.$ obtained on a principal amount at $5$ $p.c.p.a.$ after $2$ years is $Rs. 35$. What is the principal amount (in $Rs.$)?

The difference between the compound and simple interest on a sum of money for $2$ years at $6 \frac{1}{4} \%$ per annum is $Rs. 10$. The sum (in $Rs.$) is