Decay Factor Exponential

Which equation represents exponential decay?

The population of Townville is decreasing at a rate of 6% each year. If the starting population was 7,000 what equation represents the current population after x number of years?

A 12 inch candle starts to shrink as it melts. It decreases in height by 3% each hour that it burns. Calculate the height of the candle after 4 hours.

• 0.88 inches

• 0.00000972 inches

• 10.62 inches

• 7.78 inches

Jamie's Ford F150 truck was purchased for $29,500. Each year it's worth 80% of what it was worth the year before. Choose the equation that gives the truck's value f(x) after any number of years x.

Mrs. Reese is spending her retirement funds pretty quickly. Her account has $800,000 but she spends 1/4 of the money each year. Choose an equation that shows her current amount after x years:

A flea medicine breaks down at a rate of 20% per hour. This is the rate of decay of the medicine. The initial dose is 60 milligrams. Which of the following represent the equation the models the amount of flea medicine left in an animal?

• Because the 25 was bigger than one

• Because the 0.20 was bigger than one

• Because the 25 was less than one

• Because the 0.20 was less than one

The value of a car depreciates exponentially. Identify the decay factor is the car was worth $20,000 initially and worth $15,000 after 1 year.

• 1.33

• 0.75

• 0.66

• 0.25

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

What is the decay factor in the following model?
A=1200(.85)⁶

• 1200

• -.15

• .85

• A