Problem:
A bus company believes that it will need the following number of bus drivers during each of the next five years: year 1, 60 drivers; year 2, 70 drivers; year 3, 50 drivers; year 4, 65 drivers; year 5, 75 drivers. At the beginning of each year, the bus company must decide how many drivers to hire or fire. It costs $4000 to hire a driver and $2000 to fire a driver. A drivers salary is $10,000 per year. At the beginning of year 1, the company has 50 drivers. A driver hired at the beginning of the year can be used to meet the current year's requirements and is paid a full salary for the current year.
Q: Determine how to minimize the bus company's salary, hiring, and firing costs over the next 5 years.