### 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: Homework Help ✎

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 $12,250 depreciates by 11% per year.

If the value of the car decreases by 11% every year, then the car is worth 89% of the cost of it during the previous year.

Years; 0.89; 12,250

An investment of $1000 earns 6% annual interest, compounded monthly.

Use a similar process as in part (a) above.