Final answer:
Using proportions, the length of a 600-mile road on a map where 1 inch represents 30 miles is calculated to be 20 inches, equivalent to option (A).
Step-by-step explanation:
The length of a road is 600 miles, and the map scale is that one inch represents 30 miles. To find the length of the road on the map, set up a proportion comparing the actual distance to the scale distance.
Here is the proportion:
1 inch / 30 miles = x inches / 600 miles
Solving for x (the length on the map), you can multiply both sides of the proportion by 600 miles to get:
600 miles / 30 miles = x inches
This simplifies to x = 600 / 30, thus, x = 20.
Therefore, the length of the road on the map is 20 inches, which corresponds to option (A).