35 A certain transit authority must repair 120 subway cars/month. At the same time, the authority must refurbish 60 subway cars. Each task can be done in the authority’s facility or can be contracted out. Private contracting increases the cost by $1000/car repaired, and by $1500/car refurbished. Car repair and refurbishing take place in three shops— namely, the assembly shop, the machine shop, and the paint shop. Repairing a single car consumes 2% of the assembly shop capacity and 2.5% of the machine shop capacity. On the other hand, refurbishing a single car takes up 1.5% of the assembly shop capacity and 3% of the paint shop capacity. Formulate the problem of minimizing the monthly expense for private contracting as a linear program, and solve it using Microsoft Excel’s