Exponential Growth & Decay

What does the model P=A(1+r)^t best represent?

• Exponential growth

• Simple Interest

• Exponential Decay

What type of function is f(x)=2(1/7)^x ?

• Exponential Growth

• Linear

• Exponential Decay

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

Jame's 70 in. giant peach doubles in size every week. Write an expression that would represent how big the peach is after 5 weeks. (Hint: doubling = increasing at a 100% rate.)

• 70(2)³⁵

• 70(2)⁵

• 2(70)⁵

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

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

What type of function is y = 7(5/4)^x?

• Exponential Growth

• Exponential Decay

• Linear

A 78 gram sample of Uranium loses half of its mass each year.  What is the exponential equation? 

• y=78(0.5)^x
• y=78(1.5)^x
• y=78(2)^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

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