When 40% of a number is added to 42, the result is the number itself. The number is :

Options

A. 105
B. 72
C. 70
D. 82

Answer

To solve the problem step by step, we can follow these instructions:

1. **Define the variable**: Let the unknown number be represented by \( x \).

2. **Set up the equation**: According to the problem, when 40% of the number \( x \) is added to 42, the result is equal to the number itself. This can be expressed as:
\[ 0.4x + 42 = x \]

3. **Isolate the variable**: To isolate \( x \), we can rearrange the equation. First, subtract \( 0.4x \) from both sides:
\[ 42 = x - 0.4x \]
This simplifies to:
\[ 42 = 0.6x \]

4. **Solve for \( x \)**: Now, to find \( x \), divide both sides of the equation by 0.6:
\[ x = \frac{42}{0.6} \]

5. **Calculate the value**: To perform the division:
\[ x = \frac{42 \times 10}{6} = \frac{420}{6} = 70 \]

6. **Conclusion**: Therefore, the number is \( 70 \).