Answer:
the temperature at 6pm was - 0.6 F
Explanation:
Temperature every three hours...
9am: - 9.2
rose 2 so you add this to the starting temperature
9am - Noon: - 9.2 + 2 = - 7.2
Noon: - 7.2
went up 12.1 so you add this to the temperature at noon
Noon - 3pm: - 7.2 + 12.1 = 4.9
3pm: 4.9
dropped 5.5 so you subtract this to the temperature at 3pm
3pm - 6pm: 4.9 - 5.5 = -0.6
6pm: - 0.6