Homework Questions
Word Problems with Exponentials and Logs
Exponential Word Problems Compounded Continuously Other compounds Half Life inc/decreasing and app/depreciation
You have decided to invest $2500 at an 8% annual rate of interest You have decided to invest $2500 at an 8% annual rate of interest. How much will you have accumulated after 4 years it is compounded: Annually? Quarterly? Daily? Continuously?
You have decided to invest $10,000 at an 6.75% annual rate of interest. How much will you have accumulated after 5 years it is compounded: Annually? Quarterly? Daily? Continuously?
A = Pert Suppose you invest $1050 at an annual interest rate of 5.5% compounded continuously. How much will you have in the account after 5 years? Suppose you invest $1300 at an annual interest rate of 4.3% compounded continuously. How much will you have in the account after three years?
Interest An initial investment of $100 is now valued at $149.18. The interest rate is 8% compounded continuously. How long has the money been invested?
Another Example: Suppose a $125,000 piece of machinery is depreciating at 8% every year. How much is it worth after 5 years? After 7 years? How long will it take for it to be worth less than $50,000?
How Long Problems? Suppose you buy a used car that costs $11,800. The expected depreciation of the car is 20% a year. When will the value be $6,500?
How Long? The population of Ramsey City is currently 250 people with a growth rate of 9% a year. How long until the population reaches 5000 people?
Half Life Problem: A hospital prepares a 100-mg supply of technetium-99mg which has a half-life of 6 hours. Write an exponential function to find the amount of technetium-99mg that remains after 75 hours.
Another Half-Life: Arsenic-74 is used to locate brain tumors. It has a half-life of 17.5 days. Write an exponential decay function for a 90-mg sample. Use the function to find the amount remaining after 6 days.
How long? Ramsey-26 is a chemical that has a half-life of 3 days. If Amy takes 300 mg of Ramsey-26, then how much is left after 37 days? How long will it take for Amy to only have 5 mgs left in her body?
Homework Pg. 342 (3, 11, 17, 21-29 odd) Worksheet Sticker worksheet