Mr. Vishnu has an initial investment of Rs.80,000 in an investment plan. After 3 years, it has grown to Rs.1,00,000, then his rate of return is

10%

The correct answer is Option (4) → 10% **

Given:

Principal $P = 80,000$, Amount $A = 1,00,000$, Time $t = 3$ years.

Let rate = $r\%$ per annum, compounded annually.

$A = P(1 + \frac{r}{100})^{t}$

$\Rightarrow 1,00,000 = 80,000(1 + \frac{r}{100})^{3}$

$\Rightarrow \frac{1,00,000}{80,000} = (1 + \frac{r}{100})^{3}$

$\Rightarrow 1.25 = (1 + \frac{r}{100})^{3}$

Take cube root:

$1 + \frac{r}{100} = (1.25)^{1/3} \approx 1.077$

$\Rightarrow \frac{r}{100} = 0.077 \Rightarrow r = 7.7\%$

Rate of return = 7.7% per annum