(30 points) A call center accepts calls 7 days a week from 8 AM to 5 PM. The management has estimated the number of people needed daily in the call center to cover incoming calls. The company's employees work 5 consecutive days per week. The salary is $100 a day on weekdays (Mon, Tue, Wed, Thurs, Fri) and $150 a day to work weekends (Sat, Sun). Formulate the problem as an integer programming problem to minimize the cost associated with staffing the call center