Exponential Decay Equations Find R

Given the sequence:
125, 25, 5, ....
Write the explicit rule:

•  t(n) = (125)(5)⁽ⁿ⁾

•  t(n) = 625(1/5)⁽ⁿ⁾

•  t(n) = 625(5)⁽ⁿ⁾

•  t(n) = 125 + 5n

Tags

CCSS.HSF.BF.A.2

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

• Growth

• Decay

Tags

CCSS.HSF-IF.C.8B

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

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 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%

Tags

CCSS.HSF-IF.C.8B

A substance starts with a mass of 310 grams and decays at 8.9% per hour. Write an equation to model the situation.

Answer explanation

The initial mass is 310 grams, so a = 310. Find the mulitplier:

100% - 8.9% = 91.1%

Covert this percent to a rate by dividing by 100.

91.1/100 = 0.911

So, b = 0.911

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

  or y=15,000(1.08)^x

• y=15,000(0.92)^x

  or y=15,000(1 - .08)^x

• y=15,000(0.08)^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

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

• y=8(15,000)^T

• y=15,000(1.08)^T

• y=15,000(0.92)^T

• y=15,000(0.08)^T

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(1 - .30)^x

• y=30(1- 5000)^x

• y=5000(1 + .30)^x

• y=5000x^x

Tags

CCSS.HSF.LE.A.2