Aubrey spends a winter day recording the temperature once every three hours for science class. At 9 am, the temperature was -4.6°F. Between 9am and noon, the temperature increased by 4.2°F. Between noon and 3pm, the temperature went down 8.3°F. Between 3pm and 6pm, the temperature decreased by 6.9°F. What was the temperature at 6pm?
