Exploring Exponential Growth and Decay in Real Life

A population of bacteria doubles every 3 hours. If the initial population is 500, which statement is true after 9 hours?

• The population after 9 hours is 8000.

• The population after 9 hours is 1000.

• The population after 9 hours is 4000.

• The population after 9 hours is 2000.

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?

• $12,000

• $5,000

• $7,680

• $10,000

A bank account earns 5% interest compounded annually. If you deposit $1,000, which statement is true about the account balance after 5 years?

• The account balance after 5 years will be approximately $1,276.28.

• The account balance after 5 years will be $1,500.

• The account balance after 5 years will be approximately $1,200.

• The account balance after 5 years will be approximately $1,100.

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

• 2.20 meters

• 2.42 meters

• 2.00 meters

• 2.80 meters

A radioactive substance decays to half its amount every 5 years. If you start with 80 grams, how much will remain after 15 years?

• 10 grams

• 20 grams

• 5 grams

• 40 grams

A smartphone's battery life decreases by 30% each year. If the battery lasts 10 hours when new, what will its life be after 2 years?

• 6.2 hours

• 3.5 hours

• 5.5 hours

• 4.9 hours

A city's population is projected to grow exponentially from 100,000 to 200,000 in 5 years. What is the growth rate per year?

• 0.1386

• 0.1

• 0.05

• 0.25

A savings account has an initial deposit of $2,000 and earns 3% interest compounded annually. Which statement is true about the total amount after 10 years?

• The total amount after 10 years will be approximately $2,687.83.

• The total amount after 10 years will be approximately $2,200.

• The total amount after 10 years will be approximately $3,000.

• The total amount after 10 years will be approximately $2,500.

A certain species of fish in a lake is decreasing by 15% each year due to pollution. If there are currently 1,200 fish, how many will be left after 4 years?

• 900

• 800

• 500

• 626

A viral video on social media gains 1,000 views in the first hour and doubles its views every hour. How many views will it have after 5 hours?

• 32000

• 16000

• 24000

• 40000