### Home > CCG > Chapter 7 > Lesson 7.2.5 > Problem7-99

7-99.

The principal’s new car cost $\35,000$ but in three years it will only be worth $\21,494$. What is the average annual percent of decrease for the three year period? Homework Help ✎

Use the exponential function: $y=a·b^x$

$a=\text{initial value}$, $b=\frac{\text{the multiplier}}{\text{growth}}$, $x=\text{the number of years}$

Solve for $b$.

After you find “$b$" convert it to a percent and subtract from $100\%$ to find the percent decrease.

Percent decrease is $15\%$.