8th Grade Growth & Decay: Word Problems Challenge

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

• 200

• 800

• 400

• 100

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

• $16,000

• $14,450

• $18,000

• $12,000

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

• 16200

• 800

A bank account earns 5% interest compounded annually. If you deposit $1,000, how much will you have after 3 years?

• 1100.50

• 1157.63

• 1200.00

• 1305.25

A tree grows at a rate of 10% per year. If it is currently 4 feet tall, how tall will it be in 5 years?

• 8.00 feet

• 5.00 feet

• 7.20 feet

• 6.44 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?

• 50 grams

• 10 grams

• 20 grams

• 33.75 grams

A certain species of fish in a lake increases its population by 30% each year. If there are currently 1,000 fish, how many will there be in 2 years?

• 1200

• 1690

• 2000

• 1500

A smartphone loses 20% of its value each year. If it was purchased for $800, what will its value be after 3 years?

• $720.00

• $512.00

• $409.60

• $640.00

A town's population is 10,000 and is decreasing by 5% each year. What will the population be in 4 years?

• 9000

• 9500

• 8146

• 7800

A savings account has an initial balance of $500 and earns 6% interest compounded annually. How much will be in the account after 4 years?

• 631.24

• 500.00

• 600.00

• 700.00