Grade 7 Exponential Growth & Decay Word Problems Quiz

A bacteria culture doubles in size every hour. If the initial amount is 5 bacteria, how many bacteria will there be after 4 hours?

• 10

• 40

• 160

• 80

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

• 54 meters

• 24 meters

• 6 meters

• 18 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?

• 4 GHz

• 2 GHz

• 8 GHz

• 16 GHz

A certain type of crystal grows in volume by a factor of 4 every month. If the initial volume is 10 cm³, what will the volume be after 2 months?

• 80 cm³

• 160 cm³

• 40 cm³

• 200 cm³

A savings account has an initial deposit of $100. If the amount in the account doubles every year, how much will be in the account after 5 years?

• 1500

• 800

• 3200

• 6400

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

• 16 pairs

• 4 pairs

• 8 pairs

• 12 pairs

A video game character's health points double every level. If the character starts with 50 health points, how many health points will they have after reaching level 4?

• 200

• 800

• 100

• 400

A plant's height triples every week. If it starts at 1 cm, how tall will it be after 5 weeks?

• 243 cm

• 162 cm

• 729 cm

• 81 cm

A population of rabbits increases by a factor of 2 every month. If there are initially 8 rabbits, how many will there be after 3 months?

• 16

• 128

• 32

• 64

A light bulb's brightness decreases by half every hour. If the initial brightness is 100 lumens, what will the brightness be after 3 hours?

• 5 lumens

• 25 lumens

• 12.5 lumens

• 50 lumens