Exponential Growth and Decay

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(0.985)^t

• y = 1500(0.015)^t
• y = 1500(1.015)^t

• y = 1500(0.85)^t

There were 417 cell phones sold at an electronics store in January. Since then, cell phone sales at this store have increased at a rate of 3.75% per month. At this rate of growth, which function can be used to determine the monthly cell phone sales x months after January?

• f(x) = 417(3.75)^x
• f(x) = 417(0.0375)^x
• f(x) = 417(1.0375)^x
• f(x) = 417(1.375)^x

Tags

CCSS.HSA.CED.A.1

CCSS.HSF.BF.A.1

CCSS.HSF.LE.A.1

CCSS.HSF.LE.A.2

CCSS.HSF.LE.B.5

• g(x) = 10x
• f(x) = 0.1x
• g(x) = 10^x
• g(x) = 10(2)^x

• 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 domain for the situation is y ≥ 0.

• x > 0
• y > 0
• x is all real numbers

• y is all real numbers

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(114.9)^x

• f(x) = 12000(85.1)^x

• f(x) = 12000(1.149)^x

• f(x) = 12000(0.851)^x

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

• f(x) = 35(0.95)^x
• f(x) = 36(0.05)^x
• f(x) = 35(1.05)^x
• f(x) = 36(1.5)^x

Tags

CCSS.HSF.IF.B.4

CCSS.HSF.LE.A.1

• This function is an example of exponential growth.
• This function has a y-intercept at (0, 200).
• The growth factor for this function is 4.
• The range for this function is y > 0.

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(0.99)^x

• A(x) = 2(1.01)^x