Exponential Decay Equations

Is this exponential growth or decay?

• Growth

• Decay

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

Classify the model as Exponential GROWTH or DECAY.
A=1200(.85)⁶

• Growth

• Decay

Write the equation that represents the table below:

• y=1/2(4)^x

• y=2(4)^x

• y=4(2)^x

• y=4(1/2)^x

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 - .30)^x

• y=30(1- 5000)^x

• y=5000(1 + .30)^x

• y=5000x^x

The function f(x) = 24500(0.84)^x models the population of a town t years after 2008. What rate is the population of the town decreasing each year?

• 24.5%

• 75.5%

• 16%

• 84%

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

What is the exponential equation? The amount of Tylenol in an adult's system decreases by 18% per hour. An adult took 500 mg of Tylenol for a headache.

• y=18(500)^x

• y=500(18)^x

• y=500(1.18)^x

• y=500(.82)^x

Due to a drought, a lake’s depth has been decreasing at a rate of 3.6% per week. Before the drought, the depth of the lake was 34 meters. Which function can be used to find the depth of the lake w weeks after the drought began?