One common type of calculation that is made frequently out there in the real world is a "fixed and variable cost problem" - what I call a Garfield problem because it's a "lump and per" scenario. You pay a fixed cost (or a lump sum) to rent the car, or have phone service. Then, in addition, you have to pay a variable cost (so much per mile or per minute). People use math all the time (or should!) to decide which company has the best plan for their needs.
For the purposes of this Forum, we are going to discuss a subject near and dear to everyone's heart these days - the price of operating your vehicle. To do this, we need to collect three types of data - our fixed costs, our variable costs and our usage. If you either don't own a car just borrow a friend's data or use a hypothetical example based on internet research. One student even did the analysis on his aircraft carrier!
A - What are your fixed monthly car expenses?
B - What are your variable monthly car expenses?
C - What is your total cost per month?
D - Approximately how many miles do you drive a month?
E - Divide C by D to figure your cost per mile.
F - What changes might you make to save money on your total car expenses?