Raj borrows Rs. 8,000, out of which Rs. 4,500 at 5% and remaining at 6%. Find the total interest paid by him in 4 years.

Answer

To solve the problem step by step, we need to calculate the simple interest for both parts of the loan Raj has taken and then sum them up.

### Step 1: Calculate the interest on the first part of the loan
1. **Identify the principal (P)** for the first part:
- P = Rs. 4,500
2. **Identify the rate of interest (R)** for the first part:
- R = 5%
3. **Identify the time (T)**:
- T = 4 years
4. **Use the formula for Simple Interest (SI)**:
\[ SI = \frac{P \times R \times T}{100} \]
5. **Substitute the values into the formula**:
\[ SI = \frac{4500 \times 5 \times 4}{100} \]
6. **Calculate the interest**:
\[ SI = \frac{90000}{100} = 900 \]
- So, the interest on the first part is Rs. 900.

### Step 2: Calculate the interest on the second part of the loan
1. **Calculate the principal (P)** for the second part:
- Remaining amount = Total amount - First part
- P = Rs. 8000 - Rs. 4500 = Rs. 3500
2. **Identify the rate of interest (R)** for the second part:
- R = 6%
3. **Identify the time (T)**:
- T = 4 years
4. **Use the formula for Simple Interest (SI)**:
\[ SI = \frac{P \times R \times T}{100} \]
5. **Substitute the values into the formula**:
\[ SI = \frac{3500 \times 6 \times 4}{100} \]
6. **Calculate the interest**:
\[ SI = \frac{84000}{100} = 840 \]
- So, the interest on the second part is Rs. 840.

### Step 3: Calculate the total interest paid
1. **Add the interest from both parts**:
\[ \text{Total Interest} = 900 + 840 = 1740 \]
- Therefore, the total interest paid by Raj in 4 years is Rs. 1740.

### Final Answer:
The total interest paid by Raj in 4 years is Rs. 1740.

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