Modeling Decreasing Exponential Functions

A population of 1500 deer decreases by 1.5% per year. At the end of 10 years, there will be approximately 1290 deer in the population. Which function can be used to determine the number of deer, y, in this population at the end of t years?

• y = 1500(1 - 0.015)^t
• y = 1500(0.015)^t
• y = 1500(1 + 0.015)^t
• y = 1500(1.5)^t

Tags

CCSS.HSF.LE.A.2

• The graph represents an exponential growth situation.
• Eventually, the car will be worth exactly $0.
• The starting value of the car was $12,000.
• The range for the situation is y ≥ 0.

An antibiotic is introduced into a colony of 12,000 bacteria during a laboratory experiment. The colony is decreasing by 14.9% per minute. Which function can be used to model the number of bacteria in the colony after x minutes?

• f(x) = 12000(1 + 14.9)^x
• f(x) = 12000(1 - 14.9)^x
• f(x) = 12000(1 + 0.149)^x
• f(x) = 12000(1 - 0.149)^x

Tags

CCSS.HSF.LE.A.2

Some banks charge a fee for a savings account that is left inactive for an extended period of time. The equation y = 5000(0.98)^x represents the amount remaining, y, of one account that was left inactive for a period of x years. What does the number 5000 represent in this situation?

• A fee charged for an inactive account
• The percent of money in the account after x years
• The amount of money in the account initially
• The amount of money in the account after x years

Tags

CCSS.HSF.LE.B.5

A child asks her dad for an allowance that starts with a penny and then doubles every day for a month. Which function can be used to model the amount of money, A, the child will receive each day, x?

• A(x) = 2(0.01)^x
• A(x) = 0.01(2)^x
• A(x) = 0.01(1 - 2)^x
• A(x) = 2(1.01)^x

Tags

CCSS.HSF.LE.A.2

• The number of players decreases by 30% each round.
• The range for the function is 1 < y < 5.
• The domain for the function is 5 < x < 65.
• The situation represented is exponential decay.

The function to find the value of a car after t years is given by v(t) = 24,000(.75)^t Which of the following statements is not true?

• The starting value of the car was $24,000.
• The y-values of the graph increase as the x-values increase.
• The value of b indicates this is an exponential decay situation.
• The horizontal asymptote is y = 0, which means the car will never have a value of $0.

Tags

CCSS.HSF.LE.B.5

The value of a car is $15,000 and depreciates at a rate of 8% per year. What is the decay factor?

• ^.08
• ^1.08
• .92
• 8

Tags

CCSS.HSF-LE.A.1C

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

• Growth
• Decay

Tags

CCSS.HSF-IF.C.8B

Classify the model as Exponential GROWTH or DECAY.
A=10(1.01)³

• Growth
• Decay

Tags

CCSS.HSF-IF.C.8B