Problem 2. RentCar is developing a replacement policy for its car fleet over a 5-year planning horizon (from the start of year 1 to the start of year 6). At the start of each year, a car is either replaced or kept in operation. A car must be in service for at least 2 years, with a maximum service life of 4 years. The table below provides the replacement cost as a function of the year a car is acquired and the number of years in operation. Equipment acquired at start of year 1 2 3 4 5 Replacement cost ($) for given years in operation 2 3 4 3800 4100 6800 4000 4800 7000 4200 5300 7200 4800 5700 5300 Formulate the problem as a network model (with a sketch), set-up the integer programming problem, and solve for the optimal replacement policy which minimizes the cost. Hint: See Example 2. Solution. Your car should be replaced after 3 years of operation at the start of year 4 ($4100), and then replaced after 2 years of operation at the start of year 6 ($4800)