A plumber charges a flat fee plus an hourly rate. The total cost , in dollars, for a job lasting hours is given by the function . Which statement best interprets the -intercept of the graph of in the -plane?
The plumber charges $75 per hour.
The total cost for a 1-hour job is $225.
The plumber charges a flat fee of $150.
The total cost increases by $150 for each hour worked.
