Exponential Rates of Growth or Decay

In the function f(x)=4(.375)^x , is this growth or decay and by how much?

• Growth by 37.5%

• Growth by 62.5%

• Decay by 37.5%

• Decay by 62.5%

In the function f(x)=1.25(0.65)^x , is this growth or decay and by how much?

• Growth by 25%

• Growth by 65%

• Decay by 25%

• Decay by 35%

Find the balance if a bank account starts with $100, has an annual rate of 4% and the money is left in the account for 12 years. Write answer as dollars and cents.

Given that a particular bacteria doubles every hour, if we start with one bacteria, how many will there be at the end of one whole day?

The population of a certain town is modeled by f(x)=6191(1.04)^x . By what percent did the population increase by each year?

An adult takes 400mg of ibuprofen. Each hour, the amount of ibuprofen in the person's system decreases by about 29%. How many mg of ibuprofen id left after 6 hours? Round to the nearest whole number.

You buy a new computer for $2,100. The computer decreases by 50% annually. When will the computer have a value of less than $500?

• Between year 1 and 2.

• Between year 2 and 3.

• Between year 3 and 4.

You drink a beverage with 120 mg of caffeine. Each hour, the caffeine in your system decreases by about 12%. How long until you have 10 mg of caffeine?

• Between 13 and 14 hours.

• Between 19 and 20 hours.

• Between 23 and 24 hours.

• Between 10 and 11 hours.

The foundation of your house has about 1,200 termites. The termites grow at a rate of 2.4% per day. How long until the number of termites doubles?

• Between 59 and 60 days.

• Between 13 and 14 days.

• Between 21 and 22 days.

• Between 29 and 30 days.

You put $100 in a savings account that earns 1% interest every year.

Identify if it is a linear or exponential function and if it shows growth or decay and by how much.

• Exponential

  Growth

  1%/year

• Exponential

  Decay

  1%/year

• Linear

  Growth

  1%/year

• Linear

  Decay

  1%/year