Answer:
per hour.
Explanation:
We can see that our graph represents a linear function. We can see that our function's values are decreasing with passing time.
To find the degrees temperature decrease per hour we will find the slope of our given line by using slope formula.

Let us substitute two y-coordinates and their corresponding x-coordinates in slope formula.

We can see that slope of our given line is -5, which means that temperature is decreasing
by every hour.