Answer:
3
Explanation:
Slope Formula:
y2 - y1/x2 - x1
Let's use (5, 15) and (8,24)
(x1, y1) = (5, 15)
(y1, y2) = (8, 24)
Substitute:
y2 - y1/x2 - x1
24 - 15/8 - 5
Solve:
24 - 15/8 - 5
9/3
= 3
Therefore the slope, or constant rate is 3.
Tip: look at the relationship between Cost and Time.
15/5 = 3
24/8 = 3
36/12 = 3
72/24 = 3
Dividing is a simple way to find the slope!