Data Exponential Functions

Suppose the population of a species of insects doubles every year. The function f\left(x\right)=1600\left(2\right)^x gives the number of insects after x years. How many insects will there be after 3 years?

• 9600

• 12,800

• 200

• 8000

• $ 819.20

• $ 1.4

• $ 140

The function y = 125(1.13)^x represents Mr. Gantz's recent investments where x is measured in years.  Which is NOT true?

• Mr. Gantz initial invested $125

• Mr. Gantz's money grows by 13% per year

• After 4 years Mr. Gantz will have about $203.81

• Mr. Gantz earns more money in year one than in year 5

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x

• y = 15(1.35)^x

• y = 15(0.35)^x

• y = 35(1.15)^x

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

Identify the initial value:

y = 6.87 (4)^x

• a = 4

• a = 6.87

• a = 3

• a = 1

Does the graph represent an exponential growth or an exponential decay function?

• Exponential Growth

• Exponential Decay

What does the y-intercept of the graph represent?

• The amount of grams the material is gaining.

• The amount of grams the material is losing.

• The amount of grams remaining after so many years.

• The initial amount of grams.

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.

Which of the following is an increasing exponential function whose y-intercept is 50?

• y = 50(.05)^x

• y = 50x - 4

• y = (2)^x + 50

• y = 50(1.4)^x