Real-World Exponential Growth and Decay Challenges

A bacteria culture doubles in size every 3 hours. If you start with 500 bacteria, how many will there be after 12 hours?

• 1000

• 4000

• 16000

• 8000

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

• $18,000

• $10,000

• $15,000

• $12,282.50

A radioactive substance has a half-life of 5 years. If you start with 80 grams, how much will remain after 15 years?

• 20 grams

• 5 grams

• 40 grams

• 10 grams

A tree grows at a rate of 10% per year. If it is currently 4 feet tall, how tall will it be after 2 years?

• 4.20 feet

• 4.84 feet

• 6.00 feet

• 5.00 feet

A population of fish in a lake decreases by 25% each year due to pollution. If there are currently 1,200 fish, how many will be left after 2 years?

• 675

• 500

• 900

• 800

A certain type of mold grows at an exponential rate. If you have 100 grams of mold and it triples every week, how much will you have after 4 weeks?

• 300 grams

• 1200 grams

• 5000 grams

• 8100 grams

A smartphone loses 20% of its value each year. If it was purchased for $800, what will its value be after 2 years?

• $512

• $640

• $720

• $400

A certain species of plant can grow to 1.5 times its size every month. If it starts at 10 cm, what will its height be after 4 months?

• 60 cm

• 30 cm

• 40 cm

• 50.625 cm

A city’s population is decreasing by 10% each year. If the current population is 50,000, what will the population be in 5 years?

• 29525

• 25000

• 32000

• 45000

A certain type of fish decreases in population by 30% each year. If there are currently 500 fish, how many will be left after 3 years?

• 400

• 250

• 171

• 300