Amy earns $500 a week at her job when she works 40 hours. When she works more than 40 hours a
week, she calculates her gross pay in dollars, G, using the equation shown below.
G= 16.50(H-40) + 500
where H represents the total number of hours worked.
If her gross pay one week was $648.50, what was the total number of hours she worked that week?