The state Department of Labor is considering the establishment of area job training centers at up to 4 sites. The following table shows the land cost (in thousands of dollars) of the 4 sites and indicates with an * the sites that could provide adequate service to each of the five regions of the state.

Site Region 1 2 3 4 Northwest — * — *

Southwest * * — *

Capital — * * —

Northeast * — — *

Southeast * * * —

Cost 43 175 60 35 The Department seeks a minimum total cost collection of sites that together could service all five regions.

(a) Formulate a discrete optimization model to decide what sites to build using decision variables yj = 1 if site j is selected and = 0 otherwise.

(b) Enter and solve your model with the class optimization software.