Exponential Growth and Decay Interest Formula

If interest is compounded monthly, how many times a year is it compounded?

• 1

• 2

• 4

• 12

What concept is represented by P in the formula?

• past years

• prime interest

• principle amount

Determine if the function represents exponential growth or exponential decay.

Identify the percent rate of change.

• exponential growth

  r = 80%

• exponential growth

  r = 60%

• exponential decay

  r = 35%

• exponential decay

  r =40%

The value of a car is $15,000 and depreciates at a rate of 8% per year. What is the decay factor?

• ^.80

• ^1.08

• .92

• 8

Name the formula.

• exponential growth

• exponential decay

• compound interest

• principal interest

You invested $400 into an account with 7.5% interest rate compounded monthly. Which equation can be used to calculate how much you will have in 7 years?

• A=7.5(1+400)^7

• A=400(1+7.5)^7

• A=400(1+.075/12)^7.5(12)

• A=400(1+7.5/12)^12(7)

Your parents invested money in an account and used the equation A=15,000(1+.06/365)^365(30)
How long was the money in the account?

• 1 year

• 15 years

• 30 years

• 6 years

You invested money in an account and used the equation A=10,000(1+.09/4)^4(10)
The interest rate is being compounded__________________.

• Daily

• Weekly

• Monthly

• Quarterly

In the formula A=P(1+r)^t
What does P mean

• Rate

• Starting Amount

• Interest as a decimal

• Final Amount

A car tire fully inflated is losing 2.5% of its air everyday. The tire originally contained 4500 cubic inches of air. Which equation could be used to represent the loss of air

• A=4500(1+2.5)^t

• A=4500(1+.025)^t

• A=4500(1-.025)^t

• A=4500(1-2.5)^t