AFM
Unit 2
Applications of Exponentials
Application Practice
1. A $22,000 truck depreciates 11% per year. Write an exponential function to model the situation. Find the value of
the function after 8 years. Round to the nearest cent.
2. A population of 2785 brown bears increases 3% each year. Write an exponential function to model each situation.
Find the value of the function after 8 years. Round to nearest integer (whole bear).
3. If you invest $2000 compounded annually at 6%, how long will it take to double your investment? Round to 3
decimal places.
4. (a) A bacteria doubles every 7 hours. The biologist has 48 bacteria now. How many will there be in 42 hours?
(b) When will there be 1200 bacteria remaining? Round to 3 decimal places.
5. Jeanine bought a car 8 years ago for $18,000. The car is now worth $3,500. Assuming a steady rate of depreciation,
use A  a(1  r )t to find the yearly rate of depreciation (express as a percent with 1 decimal place).
AFM
Unit 2
6. A population of a city grows at a rate of 5% per year. The population in 1990 was 400,000.
a) What would be the predicted current population?
b) In what year would we predict the population to reach 1,000,000?
7. A population is growing at a rate of 5% per year. In what year would we predict the population to double?
8. A hypothetical strain of bacteria doubles every 5 minutes. One single bacterium was put in a sealed bottle at 9:00
AM, and the bottle was filled at exactly 10:00 AM. At what time was the bottle one-half full?
9. If I have $500 in my account after 4 years investing at 2.5% per year, how much money did I start with?
10. The value of a car decreases in value by 25% per year. After six years, the machine is worth $7500. What was the
original value of the car?
AFM
Unit 2
The Yonkers Fine Problem
AFM
Unit 2
Comparing Rates