Exponentials with Change of Rate

The function f(x) = 12,500(0.89)^x models the value of a car x years after its purchase. Which statement is true about the value of the car?

• The value is decreasing at a rate of 11% per year.

• The value is decreasing at a rate of 89% per year.

• The value is increasing at a rate of 11% per year.

• The value is increasing at a rate of 89% per year.

Genevieve deposited $400 into her bank account. The equation A(t) = 400(1.07)^x can be used to calculate the value of her money after t years. What is the annual interest rate she is earning on her deposit?

• 0.07%

• 1.07%

• 7%

• 10%

The function V(x) = 20,000(0.87)^x models the value of a car x years after its purchase. Which best describes the rate of change in the value of the car?

• Exponential growth of 87% each year

• Exponential growth of 13% each year

• Exponential decay of 87% each year

• Exponential decay of 13% each year

The function f(x) = 250(1.12)^x models the number of students at a school x years after it opened. By what rate is the number of students increasing each year?

• 0.12%

• 0.88%

• 12%

• 88%

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%

y = 123(1.023)^x

Describe the growth/decay rate.

• Decay by 2.3%

• Growth by 2.3%

• Decay by 97.7%

• Growth by 97.7%

y = 100(0.83)^x

Describe the growth/decay rate.

• Decay by 8.3%

• Growth by 8.3%

• Decay by 17%

• Growth by 17%

y = 1056(0.145)^x

Describe the growth/decay rate.

• Decay by 14.5%

• Growth by 14.5%

• Decay by 85.5%

• Growth by 85.5%

y = 26(1.14)^x

Describe the growth/decay rate.

• Decay by 14.%

• Growth by 14%

• Decay by 86%

• Growth by 86%

y = 209(1.0096)^x

Describe the growth/decay rate.

• Decay by 0.96%

• Growth by 0.96%

• Decay by 99.04%

• Growth by 99.04%