We need to find the number of hours that passed from 5 p.m to 11 p.m and the multiply the number of hours by the average change in temperature which is -1.25.
Change in hours:
From 5 pm to 11 pm the change in hours is:
Change in temperature:
The average change per hour is -1.25 F. So to find the total change in those 6 hours, we need to multiply 6 by -1.25, we get the following:
Answer: -7.5 Fahrenheit