To solve this problem, we need to find the difference between compound interest (CI) and simple interest (SI) for a certain sum over 3 years. Given data includes:

• Compound interest for 2 years: Rs. 104
• Simple interest for 2 years on the same sum: Rs. 100

Step 1: Calculate the rate of interest per annum

We can use the relationship between CI and SI to find the rate of interest.

The formula for compound interest after 2 years (with annual compounding) is given by: $A = P \left(1 + \frac{R}{100}\right)^2$ Where:

• $A$ is the amount after 2 years.
• $P$ is the principal.
• $R$ is the rate of interest.

The interest earned (CI) is: $CI = A - P$

The formula for simple interest is: $SI = \frac{P \times R \times T}{100}$ Where:

• $T$ is the time in years.

Given that SI for 2 years is Rs. 100: $\frac{P \times R \times 2}{100} = 100$ $P \times R = 5000$

Step 2: Calculate Compound Interest for 3 years

Using the relation $P \times R = 5000$, we first need to find $R$.

Now we can approximate the difference between the compound interest and simple interest over three years for same