Mastering Exponential Growth: Grade 7 Word Problems

A bacteria culture doubles in size every hour. If the initial size is 2 bacteria, how many bacteria will there be after 5 hours?

• 64

• 16

• 128

• 32

A tree grows 3 times its height every year. If the tree is currently 2 meters tall, what will its height be after 4 years?

• 162 meters

• 81 meters

• 54 meters

• 6 meters

A computer's processing speed doubles every 2 years. If the current speed is 1 GHz, what will the speed be in 6 years?

• 8 GHz

• 4 GHz

• 2 GHz

• 16 GHz

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

• 324

• 128

• 64

• 256

A cell phone battery lasts 2 days on a full charge. If the battery life doubles every year, how long will it last after 3 years?

• 16 days

• 4 days

• 8 days

• 32 days

A certain type of plant grows 5 times its height every season. If it starts at 1 foot tall, how tall will it be after 3 seasons?

• 50 feet

• 25 feet

• 100 feet

• 125 feet

A video game character gains experience points that double every level. If the character starts with 50 points, how many points will they have after reaching level 5?

• 1600

• 800

• 400

• 3200

A population of rabbits triples every month. If there are initially 10 rabbits, how many will there be after 3 months?

• 270

• 30

• 100

• 150

A savings account earns interest that doubles every year. If you start with $100, how much will you have after 4 years?

• $400

• $200

• $800

• $1600

A light bulb's brightness decreases by half every hour. If it starts at 100 lumens, how bright will it be after 3 hours?

• 25 lumens

• 50 lumens

• 5 lumens

• 12.5 lumens