Explanation:

- We need to divide Rs39,500 into three parts.

- The ratio given is 24:15:40.

- First, we calculate the total parts: 24 + 15 + 40 = 79.

- One part is equal to Rs39,500 / 79.

- Third part = 40 parts.

- Calculate third part: (Rs39,500 / 79) * 40 = Rs20,000.

- Option 1: Rs18,000 - Not correct for third part.

- Option 2: Rs12,000 - Not correct for third part.

- Option 3: Rs7,500 - Not correct for third part.

- Option 4: Rs20,000 - This is the correct option.