Mary earns $16 an hour plus $20 an hour for every hour of overtime. overtime hours are any hours more than 30 hours for the week. part a: create an equation that shows the amount of money earned, m, for working x hours in a week when there is no overtime. (3 points) part b: create an equation that shows the amount of wages earned, t, for working y hours of overtime. hint: remember to include in the equation the amount earned from working 30 hours. (3 points) part c: mary earned $580 in 1 week. how many hours (regular plus overtime) did she work? show your work. (4 points)