Answer:
C. The value of a car at the end of a year is 8 percent less than the value at the beginning of the year.
Explanation:
An exponential function models situations in which a quantity grows or decays by a constant percentage or factor over equal intervals of time.
Let's analyze each situation:
A. The number of fish in a tank increases by five per month.
This situation represents a constant increase (addition) of fish every month. It can be modeled by a linear function, not an exponential function.
B. The number of people in a city increases by 100 every year.
This situation also represents a constant increase (addition) in the number of people per year. It can be modeled by a linear function, not an exponential function.
C. The value of a car at the end of a year is 8 percent less than the value at the beginning of the year.
This situation represents a constant percentage decrease (multiplication) in the value of the car each year. It can be modeled by an exponential function (e.g., V(t) = V_0 * (1 - 0.08)^t, where V(t) is the value of the car after t years and V_0 is the initial value of the car).
D. The value of a phone drops $100 per year.
This situation represents a constant decrease (subtraction) in the value of the phone per year. It can be modeled by a linear function, not an exponential function.