At what rate per cent per annum simple interest will Rs. 66000 amount to Rs. 72720 in 2 years?

Answer

To find the rate per cent per annum simple interest that will make Rs. 66000 amount to Rs. 72720 in 2 years, we can follow these steps:

### Step 1: Identify the given values
- Principal (P) = Rs. 66000
- Amount (A) = Rs. 72720
- Time (T) = 2 years

### Step 2: Calculate the Simple Interest (SI)
The formula for Simple Interest is:
\[ \text{SI} = \text{Amount} - \text{Principal} \]

Substituting the values:
\[ \text{SI} = 72720 - 66000 \]
\[ \text{SI} = 6720 \]

### Step 3: Use the Simple Interest formula to find the rate (R)
The formula for Simple Interest is also given by:
\[ \text{SI} = \frac{P \times R \times T}{100} \]

We need to rearrange this formula to solve for R:
\[ R = \frac{\text{SI} \times 100}{P \times T} \]

### Step 4: Substitute the values into the formula
Now, substituting the values we have:
- SI = 6720
- P = 66000
- T = 2

So,
\[ R = \frac{6720 \times 100}{66000 \times 2} \]

### Step 5: Calculate R
Calculating the denominator:
\[ 66000 \times 2 = 132000 \]

Now substituting back:
\[ R = \frac{672000}{132000} \]
\[ R = 5.09 \]

### Step 6: Conclusion
The rate per cent per annum is:
\[ R = 5.09\% \]

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