Exponential Growth and Decay: 8th Grade Challenge

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

• 1600

• 400

• 800

• 1000

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?

• $12,282.50

• $10,000

• $18,000

• $15,000

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

• 12000

• 6000

• 800

• 16200

A bank account earns 5% interest compounded annually. If you deposit $1,000, how much will you have in the account after 10 years?

• 1628.89

• 2000.00

• 1200.50

• 1500.00

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

• 2.50 meters

• 4.00 meters

• 2.93 meters

• 3.20 meters

A certain radioactive substance decays at a rate of 25% per hour. If you start with 80 grams, how much will remain after 3 hours?

• 40 grams

• 20 grams

• 33.75 grams

• 50 grams

A smartphone's battery lasts for 2 days and loses 20% of its charge each day. How much charge will be left after 2 days?

• 80%

• 50%

• 64%

• 40%

A population of fish in a lake is currently 1,000 and increases by 30% each year. What will the population be after 2 years?

• 1200

• 1500

• 2000

• 1690

A certain type of plant grows exponentially. If it starts with 10 plants and doubles every month, how many plants will there be after 6 months?

• 1280

• 640

• 320

• 2560

A piece of furniture depreciates by 10% each year. If it was originally purchased for $500, what will its value be after 5 years?

• 295.25

• $400.00

• $250.00

• $350.75