In how many years will a sum of ₹ $800$ at $10 \%$ per annum compound interest,compounded semiannually,become ₹ $926.10$?

The difference between $C.I.$ and $S.I.$ on $Rs. 700$ in $2$ years at $5 \%$ per annum is (in $Rs.$):

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

Mr. Dua invested money in two schemes $A$ and $B$ offering compound interest at $8 \%$ per annum and $9 \%$ per annum respectively. If the total amount of interest accrued through two schemes together in two years was ₹ $4818.30$ and the total amount invested was ₹ $27000$. What was the amount (in ₹) invested in scheme $A$?

$A$ sum of money at compound interest doubles itself in $15$ years. It will become eight times of itself in (in $years$):

An amount of ₹ $8000$ was deposited at simple interest for $3$ years at $7.5$ $\%$ per annum. How much more would have been gained (in ₹) had it been deposited at the same rate per cent compound interest?