Exponential Decay: Real-World Applications & Graphs

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

• 10 grams

• 20 grams

• 5 grams

• 40 grams

A certain bacteria population doubles every 3 hours. If you start with 500 bacteria, how many will there be after 12 hours?

• 10000

• 8000

• 4000

• 2000

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

• $10,240

• $12,500

• $8,000

• $15,000

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

• 25 mg

• 100 mg

• 10 mg

• 50 mg

A tree's height decreases by 10% each year due to disease. If the tree is currently 50 feet tall, what will its height be after 2 years?

• 45 feet

• 40.5 feet

• 35 feet

• 30 feet

A scientist has a sample of a substance that decays exponentially. If the initial amount is 100 grams and it has a half-life of 10 days, how much will remain after 30 days?

• 50 grams

• 5 grams

• 12.5 grams

• 25 grams

A certain type of fish population decreases by 25% each year. If there are currently 1,200 fish, how many will be left after 2 years?

• 800

• 900

• 675

• 500

A radioactive isotope has a half-life of 8 years. If you start with 160 mg, how much will remain after 24 years?

• 40 mg

• 80 mg

• 10 mg

• 20 mg

A certain type of plant loses half of its leaves every month. If it starts with 1,000 leaves, how many will it have after 3 months?

• 250

• 750

• 500

• 125

A piece of wood loses 15% of its mass each year due to decay. If it starts at 10 kg, what will its mass be after 2 years?

• 7.225 kg

• 5 kg

• 6.5 kg

• 8.5 kg