Exponential Functions from Word Problems

While in 6th grade, Heather invested $20 in a bank account  that paid 6% in annual interest.  Which equation could be used to find the balance of her account in x years?

• A = 20(1.06)^x

• A = 20(0.06)^x

• A = 20(6)^x

• A = 20(0.16)^x

Is this exponential growth or decay?

• Growth, because of 7

• Decay, because of 1.2

• Growth because of 1.2

• Decay because of 7

The following function represents a bank account. 
g(x) = 200(1.25)^x
What is the rate the bank is paying?
*Remember the rate is added or subtracted to 1 inside parenthesis*

• 200%

• 1.25%

• 25%

• 2%

Is the pictured graph growth, decay, or linear or none?  

• Exponential Growth

• Exponential Decay

• Linear

• None

Is this exponential growth or decay?

• Growth

• Decay

What is the range of this graph?

• y = 6

• (0, -4)

• y > -6

• y < -6

You have inherited land that was purchased for $30,000 in 1990. The value of the land increased by approximately 5% per year. What is the approximate value of the land in the year 2011?

• $83,579

• $10,217

• $14,963,655

• $28,500

The population of Winnemucca, Nevada, can be modeled by P=6191(1.04)^t where t is the number of years since 1990. What percent did the population increase each year?

• 104%

• 4%

• 40%

• 400%

Your shiny new boat cost $7650.  The depreciation for your boat is 14% per year. Estimate the value of your vehicle in 3 years. What is the equation that models this problem?

• y= 7650(.14)³

• y= 7650(.86)³

• y= 7650(1+.86)³

• y = 7650(1.14)³

Is the pictured graph exponential growth, exponential decay, or linear or none?  

• Exponential Growth

• Exponential Decay

• Linear

• None of the above