Adriver was fined $20.00 plus $4.00 for every mile per hour over the speed limit of 55 mph. if the fine was $76.00, how fast was the driver going?

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?