Exponential Growth & Decay: Word Problems & Calculations

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

• 4000

• 8000

• 2000

• 1000

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

• 5 grams

• 40 grams

• 10 grams

• 20 grams

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

• $10,000

• $12,000

• $5,000

A certain species of fish in a lake grows exponentially. If there are currently 200 fish and the population doubles every month, how many fish will there be in 6 months?

• 12800

• 10000

• 6400

• 4000

A tree's height increases by 50% each year. If the tree is currently 2 meters tall, how tall will it be after 2 years?

• 6 meters

• 5 meters

• 3 meters

• 4.5 meters

A certain type of bacteria dies off at a rate of 25% per hour. If you start with 1,000 bacteria, how many will remain after 4 hours?

• 200

• 750

• 500

• 316

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

• 1050.25

• 1200.00

• 1157.63

• 1100.50

A certain medication in the bloodstream decreases by half every 4 hours. If a patient starts with 200 mg, how much will be left after 12 hours?

• 50 mg

• 100 mg

• 10 mg

• 25 mg

A population of rabbits increases by 30% each month. If there are currently 150 rabbits, how many will there be after 4 months?

• 300

• 428

• 450

• 500

A certain type of plant grows exponentially. If it starts with 10 plants and doubles every week, how many plants will there be after 5 weeks?

• 200 plants

• 400 plants

• 150 plants

• 320 plants