We can solve it using the rule of three where 1 inch is equivalent to 5 feet, then how many feet are equivalent to 4 inches, so:
1 inch ----------- 5 feet
4 inches ------- X
Where X is the width of the actual driveway. So, solving for X, we get:
[tex]X=\frac{4\text{ inches}\cdot5\text{ feet}}{1\text{ inch}}=20\text{ feet}[/tex]
Answer: 20
