Assume that we must hire people to work at an airport (for this simplified problem, we will only solve for a single day; the real-life problem is much more complicated). We know we have a given demand for workers D1, D2, …, D20 every hour from period 1 (e.g. 4:00am-5:00am) to period 20 (e.g. 11pm-midnight). They either work a full-time shift of 8 hours for $200 or a part time shift of 4 hours for $120. The solution must involve whole people for each variable (e.g. you can’t hire 4.3 people at any time). Assume that workers can only start to work at 4:00am, 8:00am, 12:00pm, 4:00pm and 8:00pm. How would you formulate this problem? Provide a specific model, and then a generic model. Make sure you define all the variables, parameters clearly for the generic model.