Exponential Growth and Decay: 8th Grade Challenges

A plant grows at a rate of 2 times its height each week. If the plant is currently 3 cm tall, how tall will it be after 4 weeks?

• 12 cm

• 48 cm

• 36 cm

• 24 cm

A bacteria culture doubles in size every hour. If there are initially 50 bacteria, how many will there be after 5 hours?

• 3200

• 800

• 1600

• 400

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

• $7,680

• $5,000

• $12,000

• $10,000

A certain type of investment grows at a rate of 5% per year. If you invest $1,000, how much will it be worth after 10 years?

• 1200.50

• 1500.00

• 2000.00

• 1628.89

A computer's processing speed doubles every 2 years. If the current speed is 2 GHz, what will the speed be after 6 years?

• 4 GHz

• 8 GHz

• 32 GHz

• 16 GHz

A certain species of fish can reproduce every 3 months, doubling their population each time. If there are 10 fish now, how many will there be after 1 year?

• 200

• 160

• 120

• 80

A cell phone plan offers unlimited data for $50 a month, but the price increases by 10% each year. What will the cost be after 5 years?

• $65.00

• $75.25

• $80.53

• $90.00

A tree grows at a rate of 1.5 times its height each year. If it is currently 4 feet tall, how tall will it be after 3 years?

• 10 feet

• 8 feet

• 13.5 feet

• 15 feet

A savings account earns 3% interest compounded annually. If you deposit $2,000, how much will you have in the account after 5 years?

• 2500.00

• 2000.00

• 3000.00

• 2318.55

A video game character's experience points double every level. If the character has 200 experience points now, how many will they have after reaching level 5?

• 12800

• 3200

• 6400

• 4000