I think the answer is C. (a.k.a the third one)
I hoped this helped !!
X = the number of months the tire was used
y = the thickness of the tire tread
y = -(3/7)x + 20
Substitute x for 20 (the number of months the tire was used) and solve for y.
The next question: Substitute x for 49 (the number of months the tire was used) and solve for y.
The is the correct answer x=80
