Exponential growth and decay

Grade 9 Math Worksheet

NameDate

Circle the best answer, or write your answer on the line.

  1. Esme's school robotics club grows by 12% each year. What number goes on each arrow of the growth table?

  2. Each wash fades the dye in Jun's shirt by 6%. What number goes on each arrow of the growth table?

  3. Kira's town has 2.5% more people each year. What number goes on each arrow of the growth table?

  4. 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?

  5. A science video starts with 250 yeast cells that grow 20% each hour. Ren watches. To the nearest whole number, how many cells are there after 4 hours?

  6. A town's population is y = 7500(1.06)^t after t years. Ari wonders: by what percent does it grow each year?

  7. A used scooter's value is y = 240(0.97)^t after t months. Bo asks: by what percent does it drop each month?

  8. Jun's town has 6,000 people and shrinks 4% each year. Which equation gives the amount y after t years?

    • y = 6000(1.04)^t
    • y = 6000(0.96)^t
    • y = 6000(0.04)^t
    • y = 6000 − 240t
  9. 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
  10. Milo's bike club has 50 members and grows 8% each month. Which equation gives the amount y after t months?

    • y = 50(1.08)^t
    • y = 50 + 4t
    • y = 50(0.08)^t
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Exponential growth and decay

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

  1. Esme's school robotics club grows by 12% each year. What number goes on each arrow of the growth table?

    1.12
  2. Each wash fades the dye in Jun's shirt by 6%. What number goes on each arrow of the growth table?

    0.94
  3. Kira's town has 2.5% more people each year. What number goes on each arrow of the growth table?

    1.025
  4. 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?

    5217
  5. A science video starts with 250 yeast cells that grow 20% each hour. Ren watches. To the nearest whole number, how many cells are there after 4 hours?

    518
  6. A town's population is y = 7500(1.06)^t after t years. Ari wonders: by what percent does it grow each year?

    6
  7. A used scooter's value is y = 240(0.97)^t after t months. Bo asks: by what percent does it drop each month?

    3
  8. Jun's town has 6,000 people and shrinks 4% each year. Which equation gives the amount y after t years?

    • y = 6000(1.04)^t
    • y = 6000(0.96)^t
    • y = 6000(0.04)^t
    • y = 6000 − 240t
  9. 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
  10. Milo's bike club has 50 members and grows 8% each month. Which equation gives the amount y after t months?

    • y = 50(1.08)^t
    • y = 50 + 4t
    • y = 50(0.08)^t