Exponential Growth and Decay

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 + 0.35)^x

• y = 15(0.35)^x

• y = 35(1+ 0.15)^x

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+ 0.14)^x

• y=6(1 - 0.14)^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

• $16,710.94

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

Change 6.75% to a decimal.

• 67.5
• .675
• 675
• .0675

Semi-Annually means how many times a year?

• 4 
• 2
• 1
• 6

Bruno was given $2000 when he turned 3 years old.  His parents invested it at a 2% interest rate compounded annually.  No deposits or withdrawls were made.  Which expression can be used to determine how much money Bruno had in the account when he turned 16? 

• 2000(1+0.02)¹³
• 2000(1-0.02)¹³
• 2000(1+0.02)¹⁶
• 2000(1-0.02)¹⁶

If the decay rate is 20%, which of the following represent the decay factor?

• 0.2

• 0.8

• 1.2

• 1.8

If the growth rate is 80%, what is the growth factor?

• 0.2

• 0.8

• 1.2

• 1.8

Pick the equation that is exponential growth

• y=2(0.5)^x
• y = 0.5(2)^x