Answer: 24/35 miles
Explanation:
Since the area = length x width, and we know that the area is 3/5 miles while the length is 7/8 miles, we can input the following equation:
3/5 miles = 7/8 miles x width
By multiplying both sides by 8/7 to isolate the width, we can calculate that the width is 24/35 miles.