Rob works for $8.00 per hour. his regular hours are 40 hours per week and he gets time-and-a-half for overtime. one week he works 50 hours. he wants to calculate his pay.

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?