Mastering Exponential Growth & Equations: Grade 8 Quiz

A bacteria culture doubles in size every 3 hours. If there are initially 500 bacteria, how many will there be after 12 hours?

• 1000

• 4000

• 16000

• 8000

A car's value decreases by 20% each year. If the car is currently worth $15,000, what will its value be after 3 years?

• $7,680

• $12,000

• $9,600

• $10,000

A population of rabbits grows exponentially. If there are 200 rabbits now and the population doubles every year, how many rabbits will there be in 5 years?

• 1600

• 3200

• 6400

• 800

A bank offers an interest rate of 5% compounded annually. If you deposit $1,000, how much money will you have after 4 years?

• 1215.51

• 1100.00

• 1300.00

• 1000.00

A certain species of fish in a lake grows at a rate of 10% per year. If there are currently 1,000 fish, how many will there be in 2 years?

• 1210

• 1300

• 900

• 1100

A tree grows at a rate of 15% per year. If the tree is currently 4 feet tall, how tall will it be after 3 years?

• 6.08 feet

• 8.40 feet

• 7.25 feet

• 5.00 feet

A town's population is currently 50,000 and is expected to grow by 8% each year. What will the population be in 4 years?

• 60000

• 68025

• 75000

• 72000

A certain investment grows exponentially. If you invest $2,000 and it grows to $3,200 in 3 years, what is the annual growth rate?

• 5%

• 16.9%

• 10%

• 25%

A virus spreads exponentially. If there are 100 infected individuals and the number of infections doubles every week, how many will be infected after 4 weeks?

• 800

• 1600

• 400

• 3200

A smartphone's battery life decreases by 25% each year. If the battery lasts 10 hours when new, how long will it last after 2 years?

• 5.625 hours

• 4 hours

• 6 hours

• 7.5 hours