Exponential Decay Formula

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

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

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

Tags

CCSS.HSF.LE.A.2

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

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(1 - .30)^x

• y=30(1- 5000)^x

• y=5000(1 + .30)^x

• y=5000x^x

Tags

CCSS.HSF.LE.A.2

Tags

CCSS.HSF.LE.A.2

Due to a drought, a lake’s 

depth has been decreasing at a rate of 

3.6% per week. Before the drought, the 

depth of the lake was 34 meters. Which 

function can be used to find the depth of 

the lake w weeks after the drought began?

Tags

CCSS.HSF.LE.A.2

• Exponential Growth

• Exponential Decay

• Quadratic

Tags

CCSS.HSF-IF.C.8B

You buy a house for $170,000. The value of the house decreases by 9% each year

• y=9(170,000)^x

• y=170,000(.91)^x

• y=170,000(1.09)^x

• y=170,000(9)^x

Tags

CCSS.HSF.LE.A.2

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

• y=8(15,000)^x

• y=15,000(1.08)^x

• y=15,000(0.92)^x

• y=15,000(0.08)^x

Tags

CCSS.HSF.LE.A.2