Exponential growth and decay
Grade 9 Math Worksheet
Circle the best answer, or write your answer on the line.
Each squeeze takes 30% of the water left in Luz's sponge. What number goes on each arrow of the growth table?
Milo's town has 4,500 people and grows 3% each year. To the nearest whole number, how many people live there after 5 years?
Noah looks up a used bike worth $360. Its value drops 15% each year. To the nearest dollar, what is it worth after 4 years?
Pia shines 800 lux of light through 3 sheets of thick paper. Each sheet blocks 30% of the light reaching it. To the nearest whole lux, how much gets through?
Tala's water has 2000 specks per mL. A filter takes out 40% of the specks on each pass. How many specks per mL are left after 3 passes?
A used scooter's value is y = 240(0.97)^t after t months. Bo asks: by what percent does it drop each month?
Jun's town has 6,000 people and shrinks 4% each year. Which equation gives the amount y after t years?
- y = 6000 − 240t
- y = 6000(0.96)^t
- y = 6000(1.04)^t
- y = 6000(0.04)^t
A fern patch in Kira's garden bed covers 20 square cm and grows 15% each week. Which equation gives the amount y after t weeks?
- y = 20 + 3t
- y = 20(1.15)^t
- y = 20(0.15)^t
Luz shines 900 lux through layers of film, and each layer blocks 25% of the light reaching it. Which equation gives the amount y after t layers?
- y = 900(1.25)^t
- y = 900(0.75)^t
- y = 900(0.25)^t
Milo's bike club has 50 members and grows 8% each month. Which equation gives the amount y after t months?
- y = 50(0.08)^t
- y = 50 + 4t
- y = 50(1.08)^t