Econo-Cool air conditioners cost $400 to purchase, result in electricity bills of $170 per year, and last for 5 years. Luxury Air models cost $600, result in electricity bills of $140 per year, and last for 8 years. The discount rate is 21%. a. What is the equivalent annual cost of the Econo-Cool model? Note: Do not round intermediate calculations. Round your answer to 2 decimal places. b. What is the equivalent annual cost of the Luxury Air model? Note: Do not round intermediate calculations. Round your answer to 2 decimal places. c. Which model is more costeffective? Econo-Cool Luxury Air d-1. Now you remember that the inflation rate is expected to be 10% per year for the foreseeable future. What are the equivalent annual cost of the Econo-Cool and Luxury Air model? Note: Do not round intermediate calculations. Round your answers to 2 decimal places. d.2. Which model is more cost-effective? Econo.Cool Luxury Alr