To find out how many miles Elsa runs in 8 weeks, we need to calculate the total distance she runs each week and then multiply it by the number of weeks.
Each week, Elsa runs 3.75 miles on Monday, 4.25 miles on Wednesday, and 7.25 miles on Friday.
Total distance per week = 3.75 + 4.25 + 7.25 = 15.25 miles.
To find the total distance Elsa runs in 8 weeks, we multiply the distance per week by 8:
Total distance in 8 weeks = 15.25 miles/week * 8 weeks = 122 miles.
Therefore, Elsa runs a total of 122 miles in 8 weeks.