Exponential Growth Models

Classify the model as Exponential GROWTH or DECAY.
A=10(1.01)³

• Growth

• Decay

What type of function is y = 7(5/4)^x?

• Exponential Growth

• Exponential Decay

• Linear

• None of the above

Write an equation that models the following situation:
Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

• y=6(0.14)^x

• y=6(1+14)^x

• y=6(1.14)^x

• y=6(0.86)^x

The expression 12(1.015)^t models the population of elephants in a wildlife refuge after t years since 1975.
What does the value 1.015 represent?

• The number of elephants was 1,015 in 1975.

• The number of elephants increases by 1.5% each year.

• The number of elephants increases by 101.5% each year.

• The number of elephants is multiplied by 1.015 each year.

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(1 - 0.30)^x

• y=30(5000)^x

• y=5000(1 + 0.30)^x

• y=5000x^x

Steve deposited $5,000 in a savings account that pays 4% interest compounded annually. Which equation could be used to find the value of the account after 3 years?

• A = 5,000(1 + 4)³

• A = 5,000(1 + 0.04)³

• A = 5,000(1 + 0.4) x 3

• A = 5,000(0.04)³

The amount of ants in a colony, f, that is decaying can be modeled by                         f(x) = 800(.87)^x, where x is the number of days since the decay started. Suppose           f(20) = 49. Which of the following is true?

• After 20 days, there are 49 ants in the colony.

• After 49 days there are 20 ants in the colony.

• The amount of ants times 20 is 49.

• After 20 days the amount of ants remaining decreases by 49.

Which function would produce the following table?

Which of the following patterns show an exponential growth or decay pattern? (select 3 answers)

• 10, 20, 30, 40, 50 ....

• 10, 20, 40, 80, 160 ...

• 64, 16, 4, 1, 0.25 ...

• 4, 12, 36, 108 ...

• 25, 16, 9, 4, 1, 4 ...

The price of basic groceries roughly doubles every 20 years. Currently, the average family spends $150 a week. Which equation models how that price will change?

• answer not listed here