Q.Find the compound interest on ₹10,000 at 10% per annum for 2 years, compounded annually.

Compute the amount with $A=P\left(1+\tfrac{r}{100}\right)^{n}$, then subtract the principal.

With $P=10000$, $r=10$, $n=2$:

The compound interest is

$\text{CI}=A-P=12100-10000=₹2{,}100.$ …

Multiplying the first-year interest by $2$ (that gives the simple interest $₹2000$). Under compounding, year 2 e …