Exponential Functions: Growth & Decay Challenges for 8th Graders

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

• 100

• 400

• 200

• 800

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?

• $12,000

• $18,000

• $16,000

• $14,450

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

• 16200

• 800

• 24000

• 6000

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

• 8.05 feet

• 6.5 feet

• 10 feet

• 7.5 feet

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

• 1157.63

• 1100.50

• 1200.00

• 1050.25

A certain species of fish in a lake is increasing at a rate of 25% per year. If there are currently 400 fish, how many will there be in 2 years?

• 800

• 500

• 625

• 1000

A radioactive substance decays at a rate of 20% per hour. If you start with 100 grams, how much will remain after 3 hours?

• 51.2 grams

• 40 grams

• 30 grams

• 70 grams

A smartphone's battery life decreases by 10% each month. If the battery is currently at 80%, what will it be after 6 months?

• 30%

• 65%

• 42.52%

• 50%

A town's population is 10,000 and is growing at a rate of 3% per year. What will the population be in 4 years?

• 11500

• 12000

• 10500

• 11255

A certain plant species grows exponentially. If it starts with 50 plants and doubles every month, how many plants will there be after 6 months?

• 1600

• 4000

• 800

• 3200