Exponential growth and decay
Grade 9 Math Worksheet - Building Confidence
Circle the best answer, or write your answer on the line.
Esme's class tracks duckweed on a pond. Its area grows 4% each day. Growth arrows are × (1 + rate). What number goes on each arrow of the growth table?
Jun stacks sheets of tinted film over a flashlight. Each sheet blocks 7% of the light reaching it. Decay arrows are × (1 − rate). What number goes on each arrow of the growth table?
Kira's town has 3% more people each year. Growth arrows are × (1 + rate). What number goes on each arrow of the growth table?
Every arrow: × 1.1. Milo measures an algae patch on a pond each day. The growth table shows days 0 to 2 and the arrow. What is the area, in square cm, on day 3?
Every arrow: × 0.8. Noah shines a light through sheets of tissue paper, and each sheet lets 80% of the light through. How much light, in lux, gets through 3 sheets?
Every arrow: × 0.9. Pia's science-fair filter takes out 10% of the specks on each pass. How many specks per mL are left after pass 3?
Tala's science notes say y = 50(0.92)^t, where t is in hours. The factor is the number raised to the power t. What does the rule say happens each hour?
- Decay: 92% less each hour
- Growth: 8% more each hour
- Decay: 8% less each hour
Zee's plant notes say y = 30(1.25)^t, where t is in weeks. The factor is the number raised to the power t. What does the rule say happens each week?
- Decay: 25% less each week
- Growth: 25% more each week
- Growth: 125% more each week
Ari's filter notes say y = 800(0.6)^t, where t is the number of passes. The factor is the number raised to the power t. What does the rule say happens each pass?
- Growth: 40% more each pass
- Decay: 60% less each pass
- Decay: 40% less each pass
Bo's forest notes say y = 12(1.08)^t, where t is in years. The factor is the number raised to the power t. What does the rule say happens each year?
- Decay: 8% less each year
- Growth: 8% more each year
- Growth: 108% more each year