a is the fifth term of a sequence. It represents the value of a depreciating
5 asset (your car) after 5 years have gone by since its purchase.
24,000 (really, $24,000) represents the initial value of the car.
(3/4) is the common ratio. Since (3/4) is between 0 and 1, we know the car is depreciating (losing value) each year, and that the value of the car at the end of this year is (3/4) times the previous value.
