Exponential Growth and Decay Mastery

A radioactive substance decays at a rate of 5% per year. If you start with a 100-gram sample, how much will remain after 5 years?

• 77.38 grams

• 85.73 grams

• 95.10 grams

• 99.75 grams

If a population of a city is increasing at a rate of 2% per year and the current population is 1,000,000, what will be the population after 10 years?

• 1,218,994

• 1,200,000

• 1,000,000

• 1,040,000

A certain type of bacteria has an exponential growth rate of 20% per hour. If you start with a culture of 200 bacteria, how many bacteria will there be in 2 hours?

• 240

• 288

• 360

• 480

A car's value decreases by 15% each year due to depreciation. If the car is currently worth $20,000, what will its value be after 3 years?

• $14,697.25

• $15,735.00

• $17,150.00

• $12,155.00

Does this represent a growth or decay? What is the rate of growth or decay?

y=3(.55)^x

• growth

  55%

• growth

  45%

• decay

  55%

• decay

  45%

• right 1

  up 4

• left 1

  up 4

• left 1

  down 4

• right 4

  down 1