Answer:
52 miles
Explanation:
Matthew runs 20 miles in the first week. We want to increase this number by 4 each week. For this question we will use m for a variable for miles.
This will look like
20 + 4m = total miles ran
if he ran 8 miles, we will enter this number into the variable m.
20 + 4 × 8 = 52
The total miles Matthew ran was 52 miles after 8 weeks.