A rental car company charges an upfront fee to rent a car, and then charges $0.40 per mile driven. Suppose you rent a car from this company. Let (n) represent the varying number of miles that you drive in the car, and let (c) represent the total cost (in dollars) you will have to pay for the rental car. a. The number of miles driven, n, and the total cost of renting the car, c, are related by a constant rate of change.
What is this constant rate of change?