Exponential Functions Percent

y = 0.5 (1.081)^x

^{What is the initial amount}

• 1.081

• 108.1

• 8.1

• 0.5

y = 0.5 (1.081)^x

^{What percent did it grow?}

• 0.5

• 1.081

• 108.1

• 8.1

• 81

y = 5000(0.32)^x

^{What is the decay rate?}

• 32%

• 132%

• 68%

• 0.32

y = 240(1.0375)^x

^{What is the percent growth?}

• 1.0375

• 375%

• 37.5%

• 3.75%

y = 1000(0.65)^x

Is this growth or decay?

• growth

• decay

• neither

y = 0.5 (1.081)^x

^{Is this growth or decay}

• growth

• decay

• neither

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

The original value of a painting is $1400, and the value increases by 9% each year. Write an exponential growth function to model this situation.

• y=1400(1.09)^x

• y=1.09(1400)^x

• y=1400(.91)^x

• y=1.09^x

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

A population of fish starts at 8,000 and decreases by 6% per year. What is the population of fish after 10 years?

• 14327

• 4309

• 839

• 7680