Final answer:
Car A is decreasing in cost, Car B's percent change needs to be calculated, and compare the percent change of both cars.
Step-by-step explanation:
a) The cost of Car A is decreasing because the exponential function f(x) = 22,500(0.88)x has a base less than 1. This means that as x increases, the value of the function decreases. The percentage change each year can be found by subtracting the previous year's cost from the current year's cost, dividing by the previous year's cost, and multiplying by 100.
b) To find the percent change for Car B, we can calculate the percentage difference between the cost after each year. For example, the percent change between year 1 and year 2 is ((20,495.48 - 24,750) / 24,750) * 100.
c) To determine whose percent change per year is greater, compare the percentages calculated in parts a and b.