Finding Values of Exponential Functions Word Problems

Write an exponential function to model the situation. The value of a car is $18000 and is depreciating at a rate of 12% per year.

• V(t) = .88(18000)^t

• V(t) = .12(18000)^t

• V(t) = 18000(.88)^t

• V(t) = 18000(.12)^t

The value of a car is $15,000 and depreciates at a rate of 8% per year. What is the exponential equation that models this situation?

• y = 8(15,000)^x

• y = 15,000(1.08)^x

• y = 15,000(0.92)^x

• y = 15,000(0.08)^x

The equation f(x) = 300(1.06)^x is being used to calculate the amount of money in a savings account.  What does the 1.06 represent?

• 6% growth

• 6% decay

• 1.06% growth

• .06% decay

What is the a-value (or y-intercept) for the function: f(x) = 800(0.85)^x?

• 800

• 0.85

• 0.15

• x

Determine if the equation y = 15(1.35)^x represents exponential growth or decay and justify. Hint: Think about the growth and decay equations.

• Growth, because the scale factor is greater than 1

• Growth, because the scale factor is less than 1

• Decay, because the scale factor is greater than 1

• Decay, because the scale factor is less than 1

Write and exponential function for the following problem: Mrs. Madison starts the year off with 100 pencils. Each week, half of the pencils disappear. How many would be left after x weeks?

What would be the "a" value (initial value) for this problem? A local zoo has a population of 32 meerkats. They are doubling every 5 years. How many would there be in 10 years?

• 32

• 2

• 5

• 10

What would be the "b" value (multiplier) for this problem? A local zoo has a population of 32 meerkats. They are doubling every 5 years. How many would there be in 10 years?

• 32

• 2

• 5

• 10

Solve this problem: When the apocalypse began, there were 5 zombies. Each day that number tripled. How many zombies would there be after a week (7 days)?

• 22

• 9,218

• 10,935

• 915

Solve the problem: Mrs. Madison has discovered she likes to crochet. She went out an bought 7 skeins of yarn to start her collection. That collection has doubled each month. How many skeins of yarn would she have after 6 months?

• 512 skeins

• 448 skeins

• 98 skeins

• 235,298 skeins