Ritu borrowed a sum of ₹$9,000$ for $2$ years at $15\%$ p.a, interest compounded $8$ -monthly. The amount (in ₹) paid by her after $2$ years was:

Given:
Principal ($P$) = ₹$9,000$
Time ($T$) = $2$ years $=24$ months
Rate ($R$) = $15\%$ per annum

Since the interest is compounded **$8$ -monthly**:
* Number of compounding periods ($n$) = $\frac{24\text{ months}}{8\text{ months}}=3$ periods
* Periodic rate of interest ($R^{\prime }$) = $15\%\times \frac{8}{12}=10\%$ per period

The formula for the compound amount is:
$$A=P{\left(1+\frac{R^{\prime }}{100}\right)}^n$$
$$A=9000{\left(1+\frac{10}{100}\right)}^3$$
$$A=9000\times (1.1{)}^3$$
$$A=9000\times 1.331=11979$$

Thus, the amount paid is ₹$11,979$.