Hi sorry for the late response, I know the assignment was due at 5pm today but anyway here is the answer.
System:
d= 5(0.75-t)
d= 20t
20t = 3.75 -5t
Define Variables:
d = how far Carol Skied
t = time it took Carol to go up/down
Solve:
20t = 3.75 -5t
20t + 5t = 3.75 -5t + 5t
25t = 3.75
25t/25 = 3.75/25
t = 0.15
Now we plug in the time into the Distances:
20t = 3.75 - 5t
20(0.15) = 3.75 - 5(0.15)
3 = 3.75 - 0.75
3 = 3
Solution as Sentence:
Carol Skied 3 miles