Calculate the amount and the compound interest on ₹ 25,000 for 3 years, the rates of interest for the successive years being 8%, 9% and 10%, compounded annually.

Given,

P = ₹ 25,000

r₁ = 8%

r₂ = 9%

r₃ = 10%

n = 3 years

By formula,

A = $P\Big(1 + \dfrac{r$1}{100}\Big)\Big(1 + \dfrac{r2}{100}\Big)\Big(1 + \dfrac{r_3}{100}\Big)

Substituting values we get :

$\Rightarrow A = 25000 \times \Big(1 + \dfrac{8}{100}\Big) \times \Big(1 + \dfrac{9}{100}\Big) \times \Big(1 + \dfrac{10}{100}\Big) \\[1em] = 25000 \times \dfrac{108}{100} \times \dfrac{109}{100} \times \dfrac{110}{100} \\[1em] = 25000 \times \dfrac{27}{25} \times \dfrac{109}{100} \times \dfrac{11}{10}\\[1em] = \dfrac{25000 \times 27 \times 109 \times 11}{25 \times 100 \times 10} \\[1em] = 27 \times 109 \times 11 \\[1em] = ₹ 32,373.$

Compound interest = Final amount - Initial principal

= ₹ 32,373 - ₹ 25,000

= ₹ 7,373.

Hence, amount = ₹ 32,373 and compound interest = ₹ 7,373.