Exponential Growth and Decay Word Problems with Half-Life and Doubling Life

Bacteria can multiply at an alarming rate when each bacteria splits into two new cells, thus doubling. If we start with only one bacteria which can double every hour, how many bacteria will we have after half of a day?

• 1024

• 2048

• 8192

• 4096

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?

• 100.0g

• 50.0g

• 12.5g

• 8.5g

Does the following equation show growth or decay?

y=10,000*1.26^x

• Growth

• Decay

• I don't know

• It doesn't provide enough information.

An experiment begins with 20 grams of a radioactive isotope. This isotope has a half-life. If y is the mass in grams remaining after x half-lives have elapsed, which equation represents the amount of grams the isotope will weigh after 4 half-lives?

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

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 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 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 number of turkey vultures in a nature sanctuary is doubling each year. When the sanctuary opened, it was home to 204 turkey vultures. Which equation can be used to find the number of turkey vultures after x years?