Q.Find the compound interest on ₹10,000 for 1 year at 8% per annum, compounded quarterly.

For quarterly compounding, the per-period rate is $\dfrac{8}{4} = 2\%$ and the number of periods is $4 \times 1 = 4$.

Given: $P = 10000$, nominal $R = 8\%$ p.a., $T = 1$ year, compounded quarterly.

Adjust for quarterly compounding. Rate per quarter $r = \dfrac{8}{4} = 2\%$; number of periods $m = 4 \times 1 = 4$.

Method 1 — formula.

So $CI = A - P = 10824.32 - 10000 = 824.32$.

Method 2 — independent check (quarter-by-quarter).

• After Q1: $10000 \times 1.02 = 10200$.
• After Q2: $10200 \times 1.02 = 10404$. …

Rounding (1.02)^4 too early and losing paise. Keep full precision until the last step, then rou …