16. In the optimal solution to the machine-to-job assignment problem, jobs 3 and 4 are assigned to different machines. Suppose there is an extra restriction that these jobs must be assigned to the same machine. Change the model to accommodate this restriction and nd the new optimal solution. 17. In the optimal solution to the bus route assignment problem, company 2 is assigned to bus routes 6 and 7. Suppose these two routes are far enough apart that it is infeasible for one company to service both of them. Change the model to accommodate 54. General Ford produces cars in Los Angeles and Detroit and has a warehouse in Atlanta. The company supplies cars to customers in Houston and Tampa. The costs of shipping a car between various points are listed in the le P05_54.:rlsx= where a blank means that a shipment is not allowed. Los Angeles can produce up to llO cars, and Detroit can produce up to 2900 cars. Houston must receive 2400 cars, and Tampa must receive 150:) cars. 3. Determine how to minimize the cost of meeting demands in Houston and Tampa. 1]. Modify the answer to part a if shipments between Los Angeles and Detroit are not allowed. c. Modify the answer to part a if shipments between Houston and Tampa are allowed at a cost of $75 per car. 61. At the beginning of year 1, a new machine must be purchased. The cost of maintaining a machine, depending on its age, is given in the le P05_6l.xlsx. The cost of purchasing a machine at the beginning of each year is given in this same le. There is no trade-in value when a machine is replaced. The goal is to minimize the total (purchase plus maintenance) cost of having a machine for ve years. Determine the years in which a new machine should be purchased. 40. You are given a group of possible investment projects for your company's capital. For each project, you are given the NPV the project would add to the rm, as well as the cash outow required by each project during each year. Given the information in the le P06_40.xlsx, determine the investments that maximize the rm's NPV. The rm has 830 million available during each of the next ve years. All numbers are in millions of dollars. 58. During the next ve periods, the demands listed in the le P06_58.xlsx must be met on time. At the beginning of period 1_. the inventory level is 0. During each period when production occurs, a setup cost of 82500 and a per-unit production cost of $20 are incurred. At the end of