Econo$-$Cool air conditioners cost $$350$ to purchase, result in electricity bills of $$200$ per year, and last for five years. Luxury Air models

cost $$550,$ result in electricity bills of $$150$ per year, and last for eight years. The discount rate is $21\%.$

a$.$ What is the equivalent annual cost of the Econo$-$Cool model?

b$.$ What is the equivalent annual cost of the Luxury Air model?

c$.$ Which model is more cost$-$effective?

d$.$ If the inflation rate is expected to be $10\%$ per year for the foreseeable future. What is the equivalent annual cost of the Econo$-$Cool

model and Luxury Air model?

Note: Do not round intermediate calculations. Round your answers to $2$ decimal places.