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 ratio of $C.I.$ and $S.I.$ interest for the same principal and rate of interest for $2$ years is $1.2,$ find the rate of interest (in $\%$).

The principal that amounts to ₹ $4913$ in $3$ years at $6 \frac{1}{4} \%$ per annum compound interest compounded annually (in ₹) is:

$A$ certain sum of money invested at compound interest becomes $1.44$ times of itself in $2$ years. If twice this sum were lent at simple interest, in how many years would it double itself?

₹ $6,100$ was partly invested in Scheme $A$ at $10 \%$ p.a. compound interest (compounded annually) for $2$ years and partly in Scheme $B$ at $10 \%$ p.a. simple interest for $4$ years. Both the schemes pay equal interests. How much was invested (in ₹) in Scheme $A$?

What would be the compound interest (in $Rs.$) accrued on an amount of $Rs. 7850$ at the rate of $14$ $p.c.p.a.$ in $2$ years?