Exponential Functions: Growth & Decay Challenges for 8th Graders

A population of rabbits doubles every year. If there are currently 50 rabbits, how many will there be in 5 years? Graph the growth of the rabbit population over 5 years.

• 800

• 1000

• 1600

• 400

A car's value decreases by 15% each year. If the car is currently worth $20,000, what will its value be in 3 years? Solve the equation to find the value after 3 years.

• $8,500

• $12,282.50

• $15,000

• $10,000

A bacteria culture grows exponentially. If the initial amount is 200 bacteria and it triples every hour, how many bacteria will there be after 4 hours? Graph the growth over the 4-hour period.

• 12000

• 8000

• 16200

• 4000

A bank account earns 5% interest compounded annually. If you deposit $1,000, how much will you have in the account after 10 years? Solve the exponential equation to find the total amount.

• 1628.89

• 2000.00

• 1500.00

• 1200.50

A radioactive substance decays at a rate of 10% per year. If you start with 500 grams, how much will remain after 6 years? Graph the decay of the substance over time.

• 300 grams

• 265.72 grams

• 400 grams

• 150 grams

A tree grows at a rate of 20% per year. If the tree is currently 3 feet tall, what will its height be in 4 years? Solve the equation to find the height after 4 years.

• 4.5 feet

• 5.0 feet

• 8.1 feet

• 6.22 feet

A certain species of fish in a lake increases by 25% each year. If there are currently 200 fish, how many will there be in 3 years? Graph the fish population growth over the 3 years.

• 300

• 391

• 450

• 250

A loan of $5,000 has an interest rate of 8% compounded annually. How much will be owed after 5 years? Solve the exponential equation to find the total amount owed.

• 7346.64

• 6000.00

• 5000.00

• 8000.00

A certain type of mold grows exponentially. If it starts with 100 spores and doubles every 2 days, how many spores will there be after 10 days? Graph the growth of the mold over the 10 days.

• 3200 spores

• 4000 spores

• 2400 spores

• 1600 spores

A tree loses 30% of its leaves each autumn. If it starts with 1,000 leaves, how many leaves will it have left after 2 autumns? Solve the equation to find the remaining leaves after 2 years.

• 700

• 600

• 490

• 800