Answer:
Carla has been running 7 miles each day for 13 days.
Step-by-step explanation:
Carla ran 3 miles on her first day, 5 miles on her second day and then 7 miles each day onward.
Let the number of days she ran 7 miles each day = x
Total distance run by Carla = 3 + 5 + 7(x)
= 8 + 7x
If her log book shows that she has run total distance = 99 miles
Equation representing her total run will be,
8 + 7x = 99
7x = 99 - 8
7x = 91
x =
x = 13 days
Therefore, Carla has been running 7 miles each day for 13 days.