Exponential Growth or Decay Word Problems

The population of a school is 800 students and is increasing at a rate of 2% per year. Use an exponential function to find the population of the school after 9 years.

Round to the nearest whole number.

During a certain period of time, about 70 northern sea otters had an annual growth of 18%. Use an exponential function to find the number of sea otters after 4 years.

Round to the nearest whole number.

Twenty years ago, Mr. Davis purchased his home for $160,000. Since then, the value of the home has increased about 5% per year. Use an exponential function to find the value of the home today.

Round to two decimal places (like money).

• Initial amount

• Rate of growth or decay

• Time

• End amount

Using the exponential function equation f(x)=ab^x, where a is the starting value and b is the growth or decay, and x is the time, find the population of fish after 8 weeks if the population doubles every week and initially there are 1000 fish.

• 128000

• 512000

• 64000

• 256000

Using the exponential function equation f(x)=ab^x, where a is the starting value and b is the growth or decay, and x is the time, find the population of bacteria after 5 hours if it doubles every hour and initially has 100 bacteria.

• 500

• 3200

• 2000

• 1000

Using the exponential function equation f(x)=ab^x, where a is the starting value and b is the growth or decay, and x is the time, find the value of a house after 15 years if it initially worth $250,000 and increases by 5% each year.

• $405,518.75

• $500,000

• $425,000

• $375,000

Using the exponential function equation f(x)=ab^x, where a is the starting value and b is the growth or decay, and x is the time, find the population of rabbits after 6 months if the population triples every month and initially there are 50 rabbits.

• 50000

• 145800

• 3000

• 800

The population of Winnemucca, Nevada, can be modeled by P=6191(1.04)^t where t is the number of years since 1990. What is the population of the town 21 years later?

• 6191

• 9912

• 72519

• 14108

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

• 29 to 30 days

• 23 to 24 days

• 15 to 16 days

• 19 to 20 days