A rent-a-car company operates a rental-agent training program, which students complete in one month. The teachers in this program are trained rental agents, at a ratio of one for every fifteen students. Experience has shown that twenty-five students must be hired for every twenty who successfully complete the program. The demand for rental cars is seasonal and, for the next six months, requires rental agents as follows:

January 135

February 125

March 150

April 170

May 160

June 180

As of 1 January, 145 trained rental agents are available for counter work or teaching, and the personnel records indicate that 8% of the trained rental agents leave the company at the end of each month. Payroll costs per month are:

Student $350

Trained agent renting of teaching $600

Trained agent idle $500

Company policy forbids firing because of an excess of agents. Formulate a linear program that will produce the minimum-cost hiring and training schedule that meets the

demand requirements, assuming that average labor turnover rates prevail and ignoring the indivisibility of agents. Assume also that in June the training school closes for vacation.