Answer:
D. C = 480 - 60t
Explanation:
Line segment for 4 ≤ t ≤ 8
Take two points: (4, 240), (8, 0)
Find slope:
[tex]\sf slope: \dfrac{y_2 - y_1}{x_2 - x_1} \quad where\:(x_1,y_1),\:(x_2,y_2)\:are\:points[/tex]
[tex]\sf \rightarrow slope: \dfrac{0-240}{8-4} = -60[/tex]
Find equation:
[tex]\sf y - y_1 = m(x - x_1)[/tex]
[tex]\sf \rightarrow C - 0 = -60(t - 8)[/tex]
[tex]\sf \rightarrow C = -60t + 480[/tex]
[tex]\sf \rightarrow C = 480-60t[/tex]
