Growth and Decay Problems

3.1(0.78)^t
Is the function growth or decay?
Check the box:

• Growth

• Decay

You start an account with $500 and an interest rate of 6% compounded yearly. How much is in the account after 3 years?

Round to the nearest cent. (two decimal places)

From 2000 - 2010 a city had a 2.5% annual decrease in population. If the city had 2,950,000 people in 2000, determine the city’s population in 2008.

Round to the nearest..... (these are people)... so whole number!

You buy a car for $8000 that depreciates at a rate of 11% a year. How much is the car worth after 5 years?

Round to the nearest cent. (two decimal places)

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

A student invests $500 for x years in a savings account that earns 4% interest per year. No further deposits or withdrawals are made during this time. Write an function f(x) to represent the amount of money earned after x years.

• f(x) = 500 (.60)^x

• f(x) = 500 (.96)^x

• f(x) = 500 (1.04)^x

• f(x) = 500 (1.4)^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(1.14)^x

• y=6(0.86)^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

Give the rate of growth:
y = 5(1.27)^x

• 127%

• 27%

• 5

Give the rate of decay:
y = 35(0.65)^x

• 35%

• 65%

• .35%

• 165%