Question

At 1:00 AM the temperature was 87º. A cold front came through and at 7:00 PM the temperature was 45°. What is the rate of change in the temperature in degrees per hour?

Answer 1

the rate of change in the temperature per hour is the quotient of the change of temperature divided by the change in hours. Since we have

1:00 AM =1 hr - 87 degrees

7:00 PM=19 hrs - 45 degrees,

then the rate is

$\frac{45-87\text{ }}{19-1}=\frac{-42}{18}=-\frac{7}{3}=-2.33$

Then, the temperature changed -2.33 degrees per hour.