Exponential Equations and Growth: Word Problems for 9th Grade

A bacteria culture doubles in size every 3 hours. If the initial population is 500, how many bacteria will there be after 12 hours?

• 10000

• 4000

• 2000

• 8000

The value of a car decreases exponentially. If a car is worth $20,000 and loses 15% of its value each year, what will its value be after 4 years?

• 10440.13

• 12000.50

• 8500.75

• 15000.00

A certain investment grows exponentially at a rate of 8% per year. If you invest $1,000, how much will it be worth after 5 years?

• 1200.00

• 1469.33

• 1000.00

• 2000.00

A tree grows exponentially, reaching a height of 2 meters in its first year and doubling its height every subsequent year. What will be the height of the tree after 4 years?

• 32 meters

• 4 meters

• 16 meters

• 8 meters

A population of fish in a lake is modeled by the equation P(t) = 200e^(0.3t), where P is the population and t is the time in years. What will the population be after 5 years?

• 500

• 1200

• 896

• 750

A smartphone's battery life decreases exponentially. If it starts with a full charge of 100%, and loses 20% of its charge every hour, how much charge will be left after 3 hours?

• 75%

• 51.2%

• 60%

• 40%

A certain species of plant grows exponentially. If the initial number of plants is 50 and it triples every month, how many plants will there be after 6 months?

• 5000

• 36450

• 100000

• 15000

A town's population is 10,000 and is expected to grow at a rate of 5% per year. Write an exponential equation to model the population after t years and find the population after 10 years.

• 12000

• 16289

• 20000

• 15000

A viral video on social media gains views exponentially. If it starts with 1,000 views and doubles every day, how many views will it have after 7 days?

• 64000

• 256000

• 128000

• 32000

A savings account earns interest at an annual rate of 6%, compounded annually. If you deposit $2,000, how much will be in the account after 3 years?

• $2,500.00

• $2,000.00

• $2,100.00

• $2,382.03