8.3 Exponential Growth and Decay

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

Tags

CCSS.HSF.LE.A.2

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

Tags

CCSS.HSF.LE.A.2

Some banks charge a fee for a savings account that is left inactive for an extended period of time. The equation y = 5000(0.98)^x represents the amount remaining, y, of one account that was left inactive for a period of x years. What does the number 5000 represent in this situation?

• A fee charged for an inactive account
• The percent of money in the account after x years
• The amount of money in the account initially
• The amount of money in the account after x years

Tags

CCSS.HSF.LE.B.5

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

Tags

CCSS.HSF.LE.A.2

Daniel’s Print Shop purchased a new printer for $35,000. Each year it depreciates at a rate of 5%. How much will the printer be worth in 8 years?

• $23,219.72
• $136.72
• $51,710.94
• $16,710.94

Tags

CCSS.7.RP.A.3

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

Tags

CCSS.7.RP.A.3

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?

• 9766
• 9006
• 9765
• 5433

Tags

CCSS.HSF.BF.A.2

What is the initial value for the function: f(x) = 300(1.16)^x?

• 300

• 1.16

• .16

• x

Tags

CCSS.HSF.IF.A.2

CCSS.HSF.LE.B.5

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

• y = 15(35)^x
• y = 15(1.35)^x
• y = 15(0.35)^x
• y = 35(1.15)^x

Tags

CCSS.HSF.LE.A.2

What is b, the common ratio, for the function: f(x) = 300(1.16)^x?

• 300
• 1.16
• .16
• x

Tags

CCSS.HSA.SSE.A.1

CCSS.HSF.LE.A.1

CCSS.HSF.LE.B.5