Thomas estimates that the costs of insurance, license, and depreciation to operate his car total $580 per month and that the gas, oil, and maintenance costs are 40 cents per mile. Thomas also estimates that, on average, he drives his car 1,800 miles per month.

Required:
a. How much cost would Thomas expect to incur during September if he drove the car 2,256 miles?
b. Would it be meaningful for Thomas to calculate an estimated average cost per mile for a typical 1,800-mile month? Explain your answer.