In the post office example, suppose that each full-time employee works eight hours per day. Thus, Monday's requirement of 17 workers can be viewed as a requirement 8(17) = 136 hours. The post office can meet its daily labor requirements by using both full-time and part-time employees. During each week, a full-time employee works eight hours a day for five consecutive days, and a part-time employee works four hours a day for five consectutive days. A full-time employee costs the post office $15 per hour, whereas a part-time employee (with reduced fringe benefits) costs the post office only $10 per hour. Union requirements limit part-time labor to 25% of weekly labor requirements.

a. Modify the model as neccesary, and then use Solver to minimize the post office's weekly labor costs.