Exponential Growth and Decay Application

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

• y=5000(0.7)^x

• y=30(5000)^x

• y=5000(1.3)^x

• y=5000x^x

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

The number of mosquitoes at the beginning of the summer was 4,000. The population of mosquitoes is expected to grow at a rate of 25% a month. How many mosquitoes will there be after 4 months?

• 9766

• 9006

• 9765

• 5433

A population of fish starts at 8,000 and decreases by 6% per year. What is the population of fish after 10 years?

• 14327

• 4309

• 839

• 7680

• A

• B

• C

• D

Which equation should be used for this problem? (Hint: Look for a key word!)

• a(1 - %)^x

• a(1 + %)^x

The following graph is an example of:

• Linear Growth

• Quadratic Decay

• Exponential Growth

• Exponential Decay

What is the growth rate of this model?

• 1.12

• 112%

• 12%

• 5000

Is the following function and example of decay or growth?

f(x)=2(0.85)^x

• Exponential Decay

• Exponential Growth

Is this exponential growth or decay?

• Growth

• Decay