Alg 1 6.D Review

If the function f(x) = 4500(.75)^x, represents the amount of money John has left to pay on his school loans, what is the decay rate?

• 4500

• .75

• 75%

• 25%

A sculpture is increasing in value at a rate of 9% per year, and its value in 2000 was $1500. Write an exponential growth function to model this situation.

• f(t)=1500(1.09)^t
• f(t)=1500(0.09)^t
• f(t)=2000(0.09)^t
• f(t)=1500(9)^t

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(0.7)^x
• y=30(5000)^x
• y=5000(1.3)^x
• y=5000x^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. Write a function to model the population of the mosquitoes.

Write an equation that models the following situation:
Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

• y=6(0.14)^x
• y=6(1+14)^x
• y=6(1.14)^x
• y=6(0.86)^x

Daniel’s Print Shop purchased a new printer for $35,000. Each year it depreciates at a rate of 5%. Write a function that shows the value of the printer.

The population of a town is 2500 and is decreasing at a rate of 3.5% per year. Write an exponential function to show the population of the town.

In 1980 there were 900 residents of Sillycity. The number of residents increases by 60% every year. Write an exponential growth function to model this situation.

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