Answer:
At 9 p.m., the temperature was -4.2 degrees.
Step-by-step explanation:
The amount of time from 8 p.m. to midnight is 4 hours.
In 4 hours, the temperature changed -16.8 degrees.
The rate of change of temperature is
-16.8 degrees / 4 hours = -4.2 degrees/hour
The temperature changes -4.2 degree in each hour.
From 8 p.m. to 9 p.m., it is 1 hour, so the temperature went from 0 degrees to -4.2 degrees.
Answer: At 9 p.m., the temperature was -4.2 degrees.
