Answer: 2.4
Explanation:
The average rate of change is found with the equation (y2 - y1) / (x2 - x1). Y refers to the outside air temp, and x refers to the number of hours since 9 am.
Find points:
9:30 is 0.5 hours after 9. Find 0.5 on the table. The y value that it corresponds to is 57. This means that point one is (0.5, 57).
12 is 3 hours after 9. Point 2 is (3, 63).
Plug numbers into equation:
x1 = 0.5
x2 = 3
y1 = 57
y2 = 63
(63 - 57) / (3 - 0.5) = 2.4