What is the difference between the compound interest on ₹$8,000$ at $15\%$ p.a. for $2$ years when the interest is compounded yearly and when compounded 8-monthly?

Given:Principal ($P$) = ₹$8,000$ Rate ($R$) = $15\%$ per annumTime ($T$) = $2\text{ years}$ Case 1: Interest is compounded yearlyNumber of periods ($n$) = $2$ Rate per period = $15\%$ $
${\text{Amount}}_1=P{\left(1+\frac{R}{100}\right)}^n=8000{\left(1+\frac{15}{100}\right)}^2$ $
$${\text{Amount}}_1=8000{\left(\frac{23}{20}\right)}^2=8000\times \frac{529}{400}=20\times 529=\text{₹}10,580$$
$${\text{CI}}_1=10580-8000=\text{₹}2,580$$
Case 2: Interest is compounded 8-monthlyTotal time = $2\text{ years}=24\text{ months}$ Number of 8-month periods ($n^{\prime }$) = $\frac{24}{8}=3$ Rate for an 8-month period ($R^{\prime }$) = $15\%\times \frac{8}{12}=10\%$ $
${\text{Amount}}_2=P{\left(1+\frac{R^{\prime }}{100}\right)}^{n^{\prime }}=8000{\left(1+\frac{10}{100}\right)}^3$ $
$${\text{Amount}}_2=8000{\left(\frac{11}{10}\right)}^3=8000\times \frac{1331}{1000}=8\times 1331=\text{₹}10,648$$
$${\text{CI}}_2=10648-8000=\text{₹}2,648$$
Difference between Compound Interests:
$$\text{Difference}={\text{CI}}_2-{\text{CI}}_1=2648-2580=\text{₹}68$$