Exponential Word Problem

A scientist is studying the growth of a bacterial colony. The initial population is 500 bacteria, and it doubles every 3 hours. How many bacteria will there be after 9 hours?

• 1000

• 2000

• 4000

• 8000

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

• 40 grams

• 5 grams

Tags

NGSS.HS-PS1-8

• 400

• 800

• 1600

• 3200

Tags

NGSS.HS-LS2-1

NGSS.HS-LS2-2

A scientist is observing the decay of a chemical compound. The compound decreases by 20% every hour. If the initial amount is 100 grams, how much will remain after 3 hours?

• 51.2 grams

• 64 grams

• 72.8 grams

• 80 grams

• 100

• 200

• 300

• 400

Tags

NGSS.HS-LS2-2

• 4050

• 1350

• 405

• 1215

Tags

NGSS.HS-PS3-1

The brightness of a star decreases exponentially with time. If the initial brightness is 1000 units and it decreases by 10% every year, what will be the brightness after 2 years?

• 810 units

• 900 units

• 1000 units

• 729 units

• 135°C

• 120°C

• 90°C

• 100°C

Tags

NGSS.HS-PS3-4

• 15 cm

• 22.5 cm

• 50.6 cm

• 50.625 cm

• 20 grams

• 40 grams

• 80 grams

• 10 grams

Tags

NGSS.HS-PS1-8