This problem mentions 'CHOICE,' which means you need to share the several possible answers that came with this problem.
There is an upfront charge of $12 per car. Next, each person in the car is charged $1. Supposing that x people are in the car, then the total cost, C(x), is
C(x) = $12 + ($1)x. This is a linear function whose domain could be, for example, [0,6], assuming that 6 people could fit into the car.
