Growth and Decay

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

A new laptop was purchased for $1,945. It decreases in value by 12.5% per year. What will be the value of the laptop after 5 years?

• $997.61

• $1,701.88

• $1,826.44

• $814.39

Twenty years ago, Mr. Davis purchased his home for $160,000. Since then, the value of the home has increased about 5% per year. How much is the home worth today?

• $176,783.29
• $424,527.63
• $57,357.75
• $532,041,076.80

Is this exponential growth or decay?

• Growth
• Decay

The original value of a painting is $1400, and the value increases by 9% each year. Write an exponential growth function to model this situation.

• y=1400(1.09)^x
• y=1.09(1400)^x
• y=1400(.91)^x
• y=1.09^x

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

A population of fish starts at 8,000 and increases by 6% per year.

What is the fish population in 10 years?

• $14,327$

• $4,309$

• $839$

• $7,680$

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

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

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=5000(0.3)^x