Exploring Exponential Growth & Half-Life Challenges

A population of bacteria doubles every 3 hours. If you start with 500 bacteria, how many will there be after 9 hours?

• 8000

• 2000

• 4000

• 1000

A certain radioactive substance has a half-life of 5 years. If you start with 80 grams, how much will remain after 15 years?

• 40 grams

• 20 grams

• 5 grams

• 10 grams

A savings account earns 4% interest compounded annually. If you deposit $1,000, how much will you have in the account after 3 years?

• 1100.00

• 1000.00

• 1124.86

• 1200.00

A tree grows at a rate of 10% per year. If the tree is currently 2 meters tall, what will its height be after 2 years?

• 2.00 meters

• 2.80 meters

• 2.42 meters

• 2.20 meters

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

• $7,680

• $5,000

• $10,000

• $12,000

A scientist has 200 grams of a substance that decays at a rate of 25% per hour. How much will remain after 4 hours?

• 63.28125 grams

• 50 grams

• 150 grams

• 100 grams

A bank offers a compound interest rate of 5% per year. If you invest $2,000, how much will you have after 5 years?

• $2,500.00

• $2,000.00

• $3,000.00

• $2,552.56

A culture of yeast grows exponentially. If you start with 300 yeast cells and they triple every hour, how many cells will you have after 4 hours?

• 8100

• 9000

• 24300

• 72900

A certain medication is effective for 8 hours and its effectiveness decreases by half every 2 hours. How effective is it after 6 hours?

• 25%

• 50%

• 0%

• 12.5%

A population of fish in a lake is currently 1,000 and increases by 50% each year. What will the population be after 2 years?

• 2000

• 2250

• 3000

• 1500