There is a $40 \%$ increase in an amount in $8$ years at simple interest. What will be the compound interest (in rupees) on ₹ $30000$ after $2$ years at the same rate?

If the difference between the $C.I.$ compounded half-yearly and simple interest on a sum at $10 \%$ per annum for one year is $Rs. 25$,the sum (in $Rs.$) is:

If a sum of money at compound interest amounts to thrice itself in $3$ years,then in how many years will it be $9$ times itself?

If the amount is $6 \frac{1}{4}$ times the principal after $2$ years at compound interest,the rate of interest (in $\%$) per annum is

How many statements are required to find the rate of interest percent $p.a.$?
$Statements:$
$I$. The difference between the compound interest and simple interest earned in two years on the amount invested is ₹ $100$.
$II$. The amount becomes ₹ $19,500$ in three years on simple interest.
$III$. The simple interest accrued in two years on the same amount at the same rate of interest is ₹ $3,000$.

What is the rate of interest (in $\%$) if simple interest earned on a certain sum for the $3^{rd}$ year is $₹ 2,000$ and compound interest earned in $2$ years is $₹ 4,160$?