1. Warm Up
If you deposit $10,000 into an account earning 3.5% interest compounded quarterly;
How much will you have in the account after 15 years?
How much more money will you have after 15 years if you compound the money daily?
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2. Compounding Interest Activity
With a partner, complete the following.
Given $1 invested at 100% for 1 year, find the following compounds. Round all answers to the ten-thousandths.
Annually?
Quarterly?
Monthly?
Weekly?

3. Continued…
Given $1 invested at 100% for 1 year, find the following compounds. Round all answers to the ten-thousandths
Daily?
Hourly?
Every minute?
Every second?
What do you notice about the answers as you compound more frequently?
What special number is it?

4. Continuously Compounding
Growth and Decay
Examples from science/nature.
Bacterial-Growth
Example: If a bacteria doubles every 20 minutes,
What is its constant or rate of growth?
If it continues to grow at that rate how much bacteria will be present in 4 hours?

5. Practice If your account compounds quarterly at 6.75%;
How much will you have to invest to have $8,000 in 15 years.
How much if you compound continuously?
If a radio-active material has a half life of 65 years;
How much will be present in 10 years?
How long until a 100 mg sample decays to 5 mgs?

6. Summary How do you tell which compounding formula to use?
What types of things compound continuously?
If you deposited $10,000 in an account earning 2.75% compounded quarterly;
How much money will you have in 15 years?
How much more would you have if it was compounded continuously?
If the half-life of a toxic chemical is 75 years, how long until a 500mg sample has reduced to 35 mg?