Ch. 6 Application Problems

Is this exponential growth or decay?

• Growth
• Decay

A new savings account is opened with $400 and gains 3% every year. What is the exponential function?

• f(x)=400(1+3)^x
• f(x)=400(1-0.03)^x
• f(x)=400(1+0.03)^x
• f(x)=400(0.03)^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

Identify the y-intercept (initial value) of the function f(x)=2(4)^x.

• 2

• 4

• (2)^x

• 8

Identify the common ratio (b value) of the function f(x)=2(4)^x.

• 2

• 4

• (2)^x

• 8

In an exponential function, what does the 'a' represent?

• Slope

• Rate of change

• Y-intercept

• Multiplier

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

The amount of ants in a colony, f, that is decaying can be modeled by                      f(x) = 800(.87)^x, where x is the number of days since the decay started. By what percentage is the colony decaying?

• 87%
• 13%
• 800%
• 8.7%

A collectible car has been going up in price by 10% each year. If the car is already worth $29,000, how much will the car be worth in 5 years?

• $0.29
• $2,900,000,000
• $46,704.79
• $145,000

The expression 12(1.015)^t models the population of elephants in a wildlife refuge after t years since 1975.
Is the population of elephants increasing or decreasing?

• Increasing
• Decreasing