`561div35.05xx19.99=?`

Options

A. 320
B. 330
C. 315
D. 325

Explanation

To solve the problem \( 561 \div 35.05 \times 19.99 \) using approximation, we can follow these steps:

### Step 1: Approximate the numbers
- **Approximate 35.05**: Since the decimal part (0.05) is less than 0.5, we round down to 35.
- **Approximate 19.99**: Since the decimal part (0.99) is greater than 0.5, we round up to 20.

### Step 2: Rewrite the expression with approximated values
Now, we can rewrite the expression:
\[ 561 \div 35 \times 20 \]

### Step 3: Perform the division
Next, calculate \( 561 \div 35 \):
- We can estimate this division. Since \( 35 \) is close to \( 36 \) (which is \( 6 \times 6 \)), we can use \( 36 \) for easier calculation.
- \( 561 \div 36 \approx 15.583 \) (but we can use \( 561 \div 35 \) directly for better accuracy).

Calculating \( 561 \div 35 \):
\[ 561 \div 35 \approx 16.03 \]

### Step 4: Multiply the result by the approximated value
Now multiply the result by 20:
\[ 16.03 \times 20 = 320.6 \]

### Step 5: Round the final result
Since we are looking for an approximate value, we can round \( 320.6 \) to \( 321 \).

### Final Answer
Thus, the approximate value of \( 561 \div 35.05 \times 19.99 \) is:
\[ \approx 321 \]