Explanation:

Let's break down the situation:

- A man invests Rs. 10,000 in each of two banks at an interest rate of 8% per annum for 2 years.

- For the first bank, simple interest is used:

$$

\text{Simple Interest} = \frac{{\text{Principal} \times \text{Rate} \times \text{Time}}}{100} = \frac{{10000 \times 8 \times 2}}{100} = Rs. 1600

$$

- For the second bank, compound interest is used:

$$

\text{Compound Amount} = \text{Principal} \times \left(1 + \frac{\text{Rate}}{100}\right)^{\text{Time}}

$$

$$

\text{Compound Amount} = 10000 \times \left(1 + \frac{8}{100}\right)^2 = 10000 \times 1.1664 = Rs. 11664

$$

$$

\text{Compound Interest} = \text{Compound Amount} - \text{Principal} = 11664 - 10000 = Rs. 1664

$$

- Total interest earned = Rs. 1600 + Rs. 1664 = Rs. 3264

- Total sum initially invested = Rs. 20000

- The percentage of total interest on initial investment:

$$

\frac{\text{Total Interest}}{\text{Total Initial Investment}} \times 100 = \frac{3264}{20000} \times 100 = 16.32\%

$$

- Option 4: 16.32%

Therefore, the correct option is option 4, as the total interest is 16.32% of the total investment.

.