Find the compound interest on $Rs. 12500$ at $8 \%$ per annum for $9$ months compounded quarterly (in $Rs.$).

Sonika invested an amount of ₹ $5800$ for $2$ years. At what rate of compound interest (in $\% \text{ p.a.}$) will she get an amount of ₹ $594.50$ as interest at the end of two years?

$A$ bank offers $5 \%$ compound interest calculated on a half-yearly basis. $A$ customer deposits ₹ $1600$ each on $1^{st}$ January and $1^{st}$ July of a year. At the end of the year,the amount (in ₹) he would have gained by way of interest is

In what time (in $years$) will ₹ $8,000$ at $3 \%$ per annum produce the same interest as ₹ $6,000$ does in $5$ years at $4 \%$ simple interest?

There is a $60 \%$ increase in an amount in $6$ years at simple interest. What will be the compound interest (in ₹) of ₹ $12000$ after $3$ years at the same rate?

The simple interest on a sum of money for $3$ years is ₹ $240$ and the compound interest on the same sum,at the same rate for $2$ years is ₹ $170$. The rate of interest is (in $\%$):