Exponential Percent Growth

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x

• y = 15(0.35)^x

• y = 15(1.35)^x

• y = 35(1.15)^x

The number of mosquitoes at the beginning of the summer was 4,000. The population of mosquitoes is expected to grow at a rate of 25% a month. How many mosquitoes will there be after 4 months?

• 9765

• 9006

• 5433

• 9766

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 child asks her dad for an allowance that starts with a penny and then doubles every day for a month. Which function can be used to model the amount of money, A, the child will receive each day, x?

• A(x) = 2(0.01)^x

• A(x) = 0.01(2)^x

• A(x) = 0.01(1 - 2)^x

• A(x) = 2(1.01)^x

Marilyn collects old dolls. She purchases a doll for $450. Research shows this doll's value will increase by 2.5% each year. Write an equation that determines the value, V, of the doll t years after purchase.

• V = 450(1 + 0.025)^t

• V = 450(1 – 0.025)^t

• V = 450(1 + 2.5)^t

• V = 450(1 – 2.5)^t

• 1.4%

• 2.8%

• 14%

• 28%

Which of the following could be represented by A=200(1.1)^t

• I started with $200 and lost 1% per week

• I started with $200 and lost 10% per week

• I started with $200 and gained 1% per week

• I started with $200 and gained 10% per week

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(1.035)^x

• y = 15(1.35)^x

• y = 15(0.35)^x

• y = 15(0.65)^x

• The value of the stock will increase over time.

• The value of the stock will decrease over time.

• The value of the stock will remain the same over time.

• The value of the stock will go up and then go down.

• The value of the stock will go down and then go up.

The function shows the growth of a fruit fly population. f(t) is the number of fruit flies after t days.

What is the initial population of the fruit flies?