Exponential Growth & Decay: Solve Word Problems for 8th Grade

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

• 1000

• 800

• 400

• 1600

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

• $15,000

• $18,000

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?

• 16200

• 2400

• 8000

• 6000

A tree grows at a rate of 10% per year. If the tree is currently 6 feet tall, how tall will it be in 2 years?

• 6.5 feet

• 9 feet

• 7.26 feet

• 8 feet

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

• 20 grams

• 10 grams

• 33.75 grams

• 50 grams

A savings account earns 5% interest compounded annually. If you deposit $1,000, how much will you have in the account after 4 years?

• 1215.51

• 1300.00

• 1100.00

• 1000.00

A certain species of fish decreases in population by 20% each year. If there are currently 1,000 fish, how many will be left after 2 years?

• 720

• 500

• 800

• 640

A new technology is adopted by 30% of the population each year. If 1,000 people initially adopt it, how many will adopt it after 3 years?

• 1800

• 1500

• 2197

• 2500

A tree's height is 12 feet and it grows at a rate of 15% per year. What will its height be after 1 year?

• 14.5 feet

• 13.8 feet

• 10 feet

• 11.5 feet

A certain type of mold doubles in size every 3 days. If you start with 5 grams, how much will you have after 12 days?

• 60 grams

• 80 grams

• 100 grams

• 40 grams