Explanation:

To solve this, let's use a simple calculation:

- Let the amount taken at 12% be X.

- Thus, the amount taken at 10% will be 36,000 - X.

- Interest from part at 12% after 2 years: $X\times \frac{12}{100}\times 2=0.24X$

- Interest from part at 10% after 2 years: $(36,000-X)\times \frac{10}{100}\times 2=0.2\times (36,000-X)$

- Total final amount paid to settle the loan is 43,920.

Now, let's solve:

- Total interest = 43,920 - 36,000 = 7,920

- Equation: $0.24X+0.2(36,000-X)=7,920$

Simplifying,

- $0.24X+7,200-0.2X=7,920$

- $0.04X=720$

- $X=\frac{720}{0.04}=18,000$

- ? Correct Answer: Option 3 - Rs. 18,000