To solve the compound interest problem, we first need to determine the interest rate.

Given:

• Amount after 1 year = INR 33,800
• Amount after 3 years = INR 43,940

Using the compound interest formula:

We have two equations:

1. P(1+r/100)=33,800
2. P(1+r/100)^3=43,940

Dividing the second by the first gives:

Taking the square root, we find r=14%

Next, for double the principal, the amount after 2 years is:

Substituting P=INR 29,652P (Approx), the amount after 2 years is approximately INR 77,030 .