Answer:
The cans are spaced 0.75 miles from each other.
Step-by-step explanation
Since the trash cans are placed at an equal distance we need to divide the total distance they cover by the number of cans that are spread across that distance in order to know how far apart they are. This is shown below:
distance between cans = (total distance)/(number of cans)
distance between cans = 13.5/18
distance between cans = 0.75 miles
The cans are spaced 0.75 miles from each other.