Exponential Growth and Compound Interest

What does the a in y=a(1+r)^x  represent?

• Time

• Rate

• Slope

• Initial Amount

You invest $400 for 5 years at an interest rate of 4.29% each year. Which equation models this?

• y=400(1 - 0.0429)⁵

• y=400(1+.0429)⁵

• y=400(1+ 4.29)⁵

• y=400e^0.049*5

Lauren has $90 in a savings account. The interest rate is 5%, compounded annually. To the nearest cent, how much will she have in 2 years?

• $99.23

• $21.98

• $56.46

• $9.21

Annual sales for a fast food restaurant are $650,000 and are increasing at a rate of 4% per year. Use an exponential function to find the annual sales after 7 years.

Round to two decimal places (like dollars and cents).

Karla invested $1,000 in savings bonds. If the bonds earn 6.75% interest compounded semi-annually, how much total will Karla earn in 15 years?

• $1,584.62

• $2,651.39

• $2,706.86

• $1,825.10

Emily would like to buy some new furniture for her home. She decides to buy the furniture on credit with 9.5% interest compounded quarterly. If she spent $7,400, how much total will she have paid after 8 years.

• $15,415.94

• $15,683.28

• $15,927.56

• $16,109.05

Jay'den earned $475 from mowing lawns last summer. He deposited this money in an account that pays an interest rate of 3.8% compounded annually. What will be his balance after 15 year?

• $827.52

• $831.10

• $839.45

• $846.80

Courtney saved up $2,200 working as a waitress over the summer. She put this money into a bank account that earned 5.2% interest and is compounded daily. How much will she have in her account at the end of 4 years?

• $2201.25

• $2694.55

• $2707.45

• $2708.63

P = 8(1.23)^x

Is the function growth or decay?

Check the box:

• Growth

• Decay

Gasoline costs $1.99 per gallon. If the price per gallon increases an average of 6% per month, which function models the exponential growth of the pricing?

• 1.06(1.99)^t

• 1.99(1.06)^t

• [1.06(1.99)]^t

• 1.99(.94)^t