Maintenance at a major theme park in central Florida is an ongoing process that occurs 24 hours a day. Because it is a long drive from most residential areas to the park, employees do not like to work shifts of fewer than eight hours. These 8-hour shifts start every four hours throughout the day. The number of maintenance workers needed at different times throughout the day varies. The following table summarizes the minimum number of employees needed in each 4-hour time period.

Time Period Minimum Employees Needed

12 a.m. to 4 a.m. ....... 90

4 a.m. to 8 a.m. .......215

8 a.m. to 12 p.m. .......250

12 p.m. to 4 p.m. .......165

4 p.m. to 8 p.m. .........300

8 p.m. to 12 a.m. .......125

The maintenance supervisor wants to determine the minimum number of employees to schedule that meets the minimum staffing requirements.

a. Formulate an LP model for this problem.

b. Create a spreadsheet model for this problem and solve it using Solver.

c. What is the optimal solution?