Answer
The unit rate in miles per hour is 2.5 mph.
Step-by-step explanation:
1/4 x 4 = 1 hour
5/8 x 4 = miles that would have been covered in one hour
20/8 of a mile would have been covered in one hour
20/8 = 2.5
2.5 miles would have been covered in an hour, with which his speed was 2.5 mph.
