Exponential Decay and Growth Word Problems

Given the function f(x) = 1.00005^x, what is the rate of change?

• .0005%

• .005%

• .05%

• .5%

• Linear Growth

• Linear Decay

• Exponential Growth

• Exponential Decay

• Because the 25 was bigger than one

• Because the 0.20 was bigger than one

• Because the 25 was less than one

• Because the 0.20 was less than one

A flea medicine breaks down at a rate of 20% per hour. This is the rate of decay of the medicine. The initial dose is 60 milligrams. Which of the following represent the equation the models the amount of flea medicine left in an animal?

The value of a car depreciates exponentially. Identify the decay factor is the car was worth $20,000 initially and worth $15,000 after 1 year.

• 1.33

• 0.75

• 0.66

• 0.25

Penicillin decays exponentially in the human body. Suppose you receive a 300-milligram dose of penicillin to combat strep throat. About 180 milligrams will remain active in your body after 1 day. How much penicillin remains after 7 days?

• 0.5 milligrams

• 8.4 milligrams

• 5 milligrams

• 120 milligrams

• Linear Growth

• Linear Decay

• Exponential Growth

• Exponential Decay

• Because the 0.25 was bigger than one

• Because the 1.3 was bigger than one

• Because the 0.25 was less than one

• Because the 1.3 was less than one

The depth of a lake is described by the function y = 334(0.976)^x , where x represents the number of weeks from today. Today, the depth of the lake is 334 ft. What will the depth be in 6 weeks? Round to the nearest tenth of a foot.

• 289 ft

• 290 ft

• 288.7 ft

• 288.6 ft

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