Yogesh borrowed Rs. 12000 at simple interest for 5 years. If he paid Rs. 3600 as simple interest after 5 years. What is the rate of interest per cent per annum ?

Options

A. 5
B. 8
C. 10
D. 6

Answer

To find the rate of interest per cent per annum, we can use the formula for simple interest:

\[ \text{Simple Interest (SI)} = \frac{P \times R \times T}{100} \]

Where:
- \( SI \) = Simple Interest
- \( P \) = Principal amount (the initial amount borrowed)
- \( R \) = Rate of interest per annum
- \( T \) = Time in years

Given:
- \( SI = 3600 \) (the simple interest paid)
- \( P = 12000 \) (the principal amount)
- \( T = 5 \) years (the time period)

We need to find \( R \).

### Step 1: Substitute the known values into the formula

We can rearrange the formula to solve for \( R \):

\[ R = \frac{SI \times 100}{P \times T} \]

Now, substituting the known values:

\[ R = \frac{3600 \times 100}{12000 \times 5} \]

### Step 2: Calculate the denominator

First, calculate the denominator:

\[ 12000 \times 5 = 60000 \]

### Step 3: Substitute the denominator back into the equation

Now substitute this value back into the equation for \( R \):

\[ R = \frac{3600 \times 100}{60000} \]

### Step 4: Calculate the numerator

Calculate the numerator:

\[ 3600 \times 100 = 360000 \]

### Step 5: Final calculation for \( R \)

Now substitute the numerator into the equation:

\[ R = \frac{360000}{60000} \]

Now perform the division:

\[ R = 6 \]

### Conclusion

The rate of interest per cent per annum is \( 6\% \).

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