`30.21% "of" 260+59.84% "of" 510-103.57=?`

Options

A. 450
B. 320
C. 210
D. 280

Explanation

To solve the expression \(30.21\% \text{ of } 260 + 59.84\% \text{ of } 510 - 103.57\), we will approximate the percentages to make the calculations easier.

### Step-by-Step Solution:

1. **Approximate the Percentages:**
- Round \(30.21\%\) to \(30\%\).
- Round \(59.84\%\) to \(60\%\).
- Round \(103.57\) to \(103\).

2. **Calculate \(30\%\) of \(260\):**
\[ 30\% \text{ of } 260 = \frac{30}{100} \times 260 = 0.3 \times 260 = 78 \]

3. **Calculate \(60\%\) of \(510\):**
\[ 60\% \text{ of } 510 = \frac{60}{100} \times 510 = 0.6 \times 510 = 306 \]

4. **Combine the Results:**
\[ 78 + 306 = 384 \]

5. **Subtract \(103\) from the Sum:**
\[ 384 - 103 = 281 \]

6. **Final Approximation:**
Since we rounded the percentages and the number, the final answer will be an approximation. The closest value to \(281\) in the options provided is \(280\).

### Final Answer:
\[ \text{The approximate value is } 280. \]