Question: A painter paints a wall in $x$ hours, so the fraction of the wall that she paints in 4 hours is
1. **State the problem:**
A painter can paint a whole wall in $x$ hours. We want to find the fraction of the wall she paints in 4 hours.
2. **Formula used:**
The fraction of work done is given by the ratio of time spent painting to the total time required.
3. **Apply the formula:**
The painter paints the entire wall in $x$ hours, so in 1 hour she paints $\frac{1}{x}$ of the wall.
4. **Calculate the fraction for 4 hours:**
In 4 hours, she paints $4 \times \frac{1}{x} = \frac{4}{x}$ of the wall.
5. **Interpretation:**
This means the painter completes $\frac{4}{x}$ of the wall in 4 hours.
**Final answer:**
$$\boxed{\frac{4}{x}}$$