An accounting firm employs part time workers and full time workers. Full time workers work 8 hours per shift while part time workers work 4 hours per shift. In addition, full time workers are paid $300 per shift while part time workers are paid $100 per shift. Currently, the accounting firm has a project requiring 500 hours of labor. If the firm has a budget of $15000, how many of each type of worker should be scheduled to minimize the total number of workers.