Management Aptitude Test 2015 Paper

(d) Given P = ₹ 10000, A = ₹ 12000 and n = 5 yr
A = P${\left(1+\frac{\mathit{r}}{100}\right)}^{\mathit{n}}$
By using the formula,
For 5 yr,
12000 = 10000${\left(1+\frac{\mathit{r}}{100}\right)}^5$
⇒ $\frac{12}{10}={\left(1+\frac{\mathit{r}}{100}\right)}^5$
⇒ $\frac{6}{5}={\left(1+\frac{\mathit{r}}{100}\right)}^5$ ...............(i)
For 20 yr,
A = 10000 ${\left(1+\frac{\mathit{r}}{100}\right)}^{20}$
= 10000${\left[{\left(1+\frac{\mathit{r}}{100}\right)}^5\right]}^4$
= 10000${\left(\frac{6}{5}\right)}^4$ [from Eq. (I)]
∴ A = 10000 × $\frac{6}{5}\times \frac{6}{5}\times \frac{6}{5}\times \frac{6}{5}$ = 216 × 6 × 16
∴ A = ₹ 20736