Sonika invested an amount of ₹ $5800$ for $2$ years. At what rate of compound interest ($\%$ per annum) will she get an amount of ₹ $594.5$ as interest at the end of two years?

On what sum will the compound interest (in ₹) for $2 \frac{1}{2}$ years at $10 \%$ per annum amount to ₹ $6352.50$?

If the compound interest on a sum for $2$ years at $12 \frac{1}{2} \%$ per annum is ₹ $510$,the simple interest (in ₹) on the same sum at the same rate for the same period of time is:

Amit invested an amount of $Rs. 25000$ in a fixed deposit at a compound interest rate of $8 \%$ per annum for $2$ years. What amount (in $Rs.$) will Amit receive at the end of the period?

The simple interest on a certain sum at $4 \%$ per annum for $2$ years is ₹ $80$. The compound interest (in ₹) on the same sum for the same period is

Which information given below is sufficient to know the principal amount if the difference between the $C.I.$ and $S.I.$ for $2$ years is $18$?
$(I)$ The rate is same at which an amount of $Rs. 1000$ becomes $1120$ in $2$ years under $S.I.$
$(II)$ The principal is $Rs. 2000$.