Final answer:
The independent and dependent quantities are the time spent painting and the total miles painted, respectively. The equation relating these quantities is y = 0.25x + 9.5, with x being the hours and y being the total miles painted.
Step-by-step explanation:
The two quantities that are changing in the situation where a painting crew is painting a 24-mile stretch of road and has already completed 9.5 miles at a rate of 0.25 mile per hour are the distance painted (dependent) and the time spent painting (independent). Let us define x as the independent variable representing the hours spent painting and y as the dependent variable representing the total miles painted. The equation relating the two is y = 0.25x + 9.5, where 9.5 represents the initial miles already painted.