### Home > CCA2 > Chapter 2 > Lesson 2.2.1 > Problem 2-85

Below are two more situations that can be described using exponential functions. They represent a small sampling of the situations where quantities grow or decay by a constant percentage over equal periods of time. For each situation:

Find an appropriate unit of time (such as days, weeks, years).

Find the multiplier that should be used.

Identify the initial value.

Write an exponential equation in the form

^{ }

The value of a car with an initial purchase price of

depreciates by per year. If the value of the car decreases by

every year, then the car is worth of the cost of it during the previous year. Years;

An investment of

earns annual interest, compounded monthly. Use a similar process as in part (a) above.