Fox
Exponential Word Problems
1. Blueville has a population of 7000. Its population is increasing at a rate of 1.4%. How
many people will live there in 8 years?
2. Waynesburg has a population of 16,000. Its population is increasing at a rate of 1.5%.
How many people will live there in 4 years?
3. Sam deposited $500 into a savings account with 3% interest, compounded yearly. How
much will he have after 6 years?
4. Lucy loans her friend $100, but charges her 5% simple interest. How much will her
friend owe in 2 years?
5. The population of trout in a certain lake is 10,000. Their population is decreasing by
1.4% each year. How many fish will be in the lake in 7 years?
6. The world population in 2000 was approximately 6.08 billion. The annual rate of
increase was 1.26%.
A. Find the growth factor.
B. How many people will be here in 2020?
7. A computer valued at $6500 depreciates at the rate of 15% per year. How much is it
worth after 4 years?
8. A tool business purchased a piece of equipment of $250,000. The value of the equipment
depreciates at a rate of 12% each year. How much is the equipment worth after 6 years?
9. The number of newly reported cases of tuberculosis (in thousands) in the US from 1991
to 1996 can be approximated by the equation 𝑇 = 28.5(0.9567)𝑡 , where t is the number of
years since 1991.
A. What is the initial amount?
B. What is the decay factor?
C. What is the decay rate?
D. How many cases will there be in 2001?
10. A new car that sells for $18,000 depreciates 25% each year. How much will the car be
worth after 2 years?
11. Paul deposited $750 at a rate of 2% compounded quarterly. How much money does he
have after 4 years.
12. Sarah bought a new car using a car loan service. The car was $40,000 and the loan
service is charging her 8% interest, compounded monthly. How much will she owe if she
makes no payments for 5 years?
13. There are 10 grams of Curium-245 which has a half-life of 9,300 years. How many
grams will remain after 37,200 years?
14. There are 80 grams of Cobalt-58 which have a half-life of 71 days. How many grams will
remain after 213 days?
15. The half-life of Rhodium-105 is 1.5 days. If there are initially 7500 grams of this isotope,
how may grams would remain after 30 days?