Heather W. answered 10/04/19
Graduate Student with Level 3 Tutoring Certification
Unit rates may seem difficult to understand, but it explains a specific unit of measurement based on a rate of time (usually).
For your problem, you are looking for how many miles Ben walked per minute — so the goal is miles per minute.
We know Ben walked a total of 3/4 of a mile (or .75 miles) and it took him 8 1/2 minutes to do it (or 8.5 minutes)
Since we want miles per minutes we need to divide the miles by the minutes.
.75 miles. = 0.088 miles per minute
8.5 minutes