Explanation:

To solve this problem, let's break it down step by step:

- Kamal invests in two schemes, A and B, in a ratio of 3:2.

- Simple interest for Scheme A is at 4% for 4 years.

- Simple interest for Scheme B is at 8% for 2 years.

- Total simple interest from both schemes is Rs. 1200.

Let’s denote the amounts invested in Schemes A and B as 3x and 2x respectively.

1. Calculate Simple Interest (SI) for each scheme:

- Scheme A:

- SI = (3x * 4% * 4) = 0.48x.

- Scheme B:

- SI = (2x * 8% * 2) = 0.32x.

2. Total SI = SI from Scheme A + SI from Scheme B = Rs. 1200:

- 0.48x + 0.32x = 1200

- 0.80x = 1200

- x = 1500

3. Find the total investment (3x + 2x):

- Amount invested = 3x + 2x = 5x

- Total amount = 5 * 1500 = Rs. 7500.

- Correct Answer: Option 3: Rs. 7500