Hi there.
First, let's convert the improper fraction to a mixed number. Then we'll find out how much 1/4 of an hour actually is.
15/2 = 7 1/2
1/4 of 60 = 15
So far, the marathon runner can run 7 1/2 miles in 15 minutes.
To find the unit rate, we multiply both by 4.
7 • 4 = 28
1/2 • 1/2 = 2
Add these and you'll get 30.
15 minutes • 4 = 60
The unit rate is:
30 miles per hour (not sure how to write this using miles)
