A manufacturing facility has 5 parallel machines that are used to produce 10 products during the next 28 days. The available time (number of hours) of each machine at each day in the planning horizon is known. These available times account for maintenance activities. Machines can work for up to twelve hours of regular time. The sum of regular time and overtime in each period should not exceed the available time. For instance, if the available time for a machine in a particular period is 16 hours, then the machine can be run for twelve hours of regular time and four hours of overtime. The cost of running a machine during regular time and overtime varies per machine but it does not vary per day. There is a production rate (number of units per hour) associated with each product and machine combination. The demand for each product is given as number of units per day. The on-hand inventory for each product is available at the beginning of the planning horizon and may be used to cover the demand for the day. There is no safety stock requirement throughout the planning horizon; however, the company wants the