The value of `20 div [ { 20 xx ( 3 - 7)} - 15 + 25 ]` is :

Options

A. `-2`
B. `7.5`
C. `10`
D. `-1.54`

Answer

To solve the expression \( 20 \div [ { 20 \times ( 3 - 7)} - 15 + 25 ] \), we will follow the order of operations (parentheses, exponents, multiplication and division from left to right, addition and subtraction from left to right).

### Step-by-Step Solution:

1. **Calculate the expression inside the parentheses**:
\[ 3 - 7 = -4 \]
Now the expression becomes:
\[ 20 \div [ { 20 \times (-4)} - 15 + 25 ] \]

**Hint**: Always start with the operations inside the parentheses.

2. **Multiply \(20\) by \(-4\)**:
\[ 20 \times (-4) = -80 \]
Now the expression is:
\[ 20 \div [ -80 - 15 + 25 ] \]

**Hint**: Remember to perform multiplication before addition and subtraction.

3. **Perform the subtraction and addition inside the brackets**:
- First, calculate \(-80 - 15\):
\[ -80 - 15 = -95 \]
- Then, add \(25\):
\[ -95 + 25 = -70 \]
Now the expression simplifies to:
\[ 20 \div -70 \]

**Hint**: Combine like terms step by step to avoid mistakes.

4. **Perform the division**:
\[ 20 \div -70 = -\frac{20}{70} = -\frac{2}{7} \]

**Hint**: Simplify fractions by dividing the numerator and denominator by their greatest common divisor.

### Final Answer:
The value of \( 20 \div [ { 20 \times ( 3 - 7)} - 15 + 25 ] \) is:
\[ -\frac{2}{7} \]