Mastering Exponential Growth and Decay for 8th Graders

A population of rabbits doubles every year. If there are currently 50 rabbits, how many will there be in 3 years?

• 400

• 100

• 200

• 800

A car's value decreases by 20% each year. If the car is currently worth $15,000, what will its value be after 2 years?

• $12,000

• $9,600

• $8,000

• $10,500

A bacteria culture grows exponentially. If there are 200 bacteria now and it triples every hour, how many bacteria will there be after 4 hours?

• 16200

• 800

• 6000

• 24000

A tree grows at a rate of 5% per year. If it is currently 10 feet tall, how tall will it be in 5 years?

• 10 feet

• 8 feet

• 15 feet

• 12.76 feet

A radioactive substance decays at a rate of 10% per hour. If you start with 100 grams, how much will remain after 3 hours?

• 90 grams

• 50 grams

• 100 grams

• 72.9 grams

A savings account earns 6% interest compounded annually. If you deposit $1,000, how much will you have in the account after 5 years?

• 1200.00

• 1500.50

• 1005.00

• 1338.23

A certain species of fish in a lake decreases by 15% each year due to pollution. If there are currently 1,200 fish, how many will be left after 4 years?

• 800

• 900

• 500

• 626

A smartphone loses 25% of its value each year. If it was purchased for $800, what will its value be after 3 years?

• $250.00

• $337.50

• $450.00

• $600.00

A town's population is 10,000 and is growing at a rate of 8% per year. What will the population be in 2 years?

• 11664

• 12000

• 11000

• 10500

A certain type of mold grows at a rate of 50% every day. If you start with 10 grams, how much will you have after 3 days?

• 50 grams

• 40 grams

• 33.75 grams

• 20 grams