Ms. Williamson woke up one morning to find her basement flooded with water. She called two different plumbers to get their rates. The first plumber charges $36 just to walk in the door plus $28 an hour. The second plumber charges a flat $64 an hour. a. What is the cost for each plumber if the job takes four hours?

b. How many hours did the first plumber take to do the job if he charged $176?

c. After how many hours will the cost for both plumbers be the same?