5 (Chapter 6) Optional. 2 points Extra Credit for perfect answer, showing work. (Hint: Do this on an Excel spreadsheet.) Operating costs of an automobile in TravelX Inc.'s automotive pool (for its employees) are as follows for a car in year t of its age (e.g., year 1, year 2, etc.) 4 2500 1000 1500 2000 4000 5000 Cost of auto replacement are $16,000. TravelX's discount rate is 10%. Salvage value if a car is sold at agetis 4 5000 13,000 10,000 6,000 3000 2000 What is the optimal age of replacement for an auto in TravelX's fleet? What is the equivalent annual cost of this auto