Real-Life Exponents: Evaluate & Solve for 8th Graders

A bacteria culture doubles in size every 3 hours. If the initial size is 100 bacteria, how many bacteria will there be after 12 hours?

• 1600

• 800

• 400

• 2000

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

• $8,000

• $12,500

• $10,240

• $15,000

A tree grows at a rate of 2^n centimeters per year, where n is the number of years since it was planted. How tall will the tree be after 5 years?

• 32 cm

• 128 cm

• 16 cm

• 63 cm

The population of a town is 1,500 and is expected to grow by 5% each year. What will the population be after 4 years?

• 1750

• 1823

• 2000

• 1600

A computer's processing speed is measured in gigahertz (GHz) and doubles every 2 years. If the current speed is 2 GHz, what will it be in 6 years?

• 32 GHz

• 4 GHz

• 16 GHz

• 8 GHz

A certain investment grows according to the formula A = P(1 + r)^t, where P is the principal amount, r is the rate, and t is the time in years. If you invest $1,000 at a rate of 5% for 3 years, how much will it be worth?

• 1100.50

• 1050.75

• 1157.63

• 1200.00

A certain species of fish can reproduce every 4 months, and each pair produces 2 offspring. If you start with 3 pairs, how many fish will there be after 1 year?

• 18

• 12

• 36

• 24

A smartphone's battery life decreases exponentially. If it lasts for 24 hours when fully charged, how long will it last after 3 cycles of use if it retains 75% of its charge each cycle?

• 18 hours

• 10.125 hours

• 15 hours

• 12 hours

A population of rabbits is modeled by the equation P(t) = 50(2^t), where t is the number of months. How many rabbits will there be after 5 months?

• 800

• 1600

• 2000

• 400

A savings account earns interest compounded annually. If you deposit $500 at an interest rate of 4%, how much will you have in the account after 5 years?

• 500.00

• 608.33

• 520.00

• 640.00