Percent of Growth or Decay

Rhonda deposited $3000 in an account in the Merrick National Bank, earning 4.2% interest, compounded annually. She made no deposits or withdrawals. Write an equation that can be used to find B, her account balance after t years.

• B = 3000(1 – 4.2)^t

• B = 3000(1 + 4.2)^t

• B = 3000(1 – 0.042)^t

• B = 3000(1 + 0.042)^t

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

A car was purchased for $25,000. Research shows that the car has an average yearly depreciation rate of 18.5%. Create a function that will determine the value, V(t), of the car t years after purchase.

• V(t) = 25000(1 – 0.185)^t

• V(t) = 25000(1 + 0.185)^t

• V(t) = 25000(1 – 18.5)^t

• V(t) = 25000(1 + 18.5)^t

The bear population in a given area is currently 1580. They anticipate the bear population to decrease by 2% each year. Which function represents the population of bears, B, after t years.

• B = 1580(0.02)^t

• B = 1580(1 – 0.02)^t

• B = 1580(1 + 0.02)^t

• B = 1580(1 – 0.2)^t

What is the percentage rate of growth or decay?

• 12%

• 88%

• .12%

• 112%

• .88%

The bear population in a given area is currently 1580. They anticipate the bear population to decrease by 2% each year. Which function represents the population of bears, B, after t years.

• B = 1580(0.02)

• B = 1580(1 – 0.02)

• B = 1580(1 + 0.02)

• B = 1580(1 – 0.2)

A used car was purchased for $8,400. The car depreciates at a rate of 5% each month. The starting value is ​ (a)   and there is ​ 5% ​ (b)   which means the scale factor is ​ (c)   .

• $8,400

• decay

• 0.95

• growth

• 0.05

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

What is the percent growth or decay of the following function?

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