Question

A skating rink charges an hourly rate plus a fee to rent skates. The graph shows the total cost, y, as a function of the number of hours skated, 2.
The initial value is
It represents
the fee to rent skates
Skating Time (h),
Total Cost ($). y 5
0
Total Cost ($)
45 y
40
35
30
25
20
15
10
>> Describe the rate of change of the function.
The rate of change is ? It represents
5(0,5)
0
0
1
2
3
4
the ?

Answer 1

Rate of change = 5 dollars per hour.

Work: using two points from the graph, e.g. (0, 5) and (1, 10), slope = (10 − 5)/(1 − 0) = 5. Units: dollars/hour. Interpretation: this is the hourly skating charge. (The initial value $5 at x = 0 is the skate-rental fee, so y = 5x + 5.)