A sum of money at compound interest amounts to thrice itself in $3$ years. In how many years will it be $9$ times itself?

The difference between the simple interest on a certain sum at the rate of $10 \%$ per annum for $2$ years and compound interest which is compounded every $6$ months is ₹ $124.05$ . What is the principal (In ₹) ?

What will be the difference between simple and compound interest (In ₹) @ $10 \%$ per annum on a sum of ₹ $1000$ after $4$ years?

If the compound interest on a certain sum for $2$ years is ₹ $105$ and simple interest is ₹ $100$, then the sum (In ₹) is

The difference between simple and compound interest on sum of $10000$ is $64$ for $2$ years. Find the rate of interest.

Which of the statement given below are sufficient to answer the following question.

What is the rate of interest per annum on an investment of $Rs. 800 ?$

($I$) The income from $S.I.$ at the end of $3$ years at the same rate of interest is $19$

($II$) $C.I.$ is $15.76$ more than $S.I.$ on same sum $\&$ same rate in $2$ years