Answer
16.67%
Explanation
Assume the initial price of sugar is 100 rupees. Due to a 20% increase, the new price is 120 rupees. To keep expenditure constant, the reduction in consumption = \( \frac{\text{increase}}{\text{new price}} \times 100 = \frac{20}{120} \times 100 = \frac{1}{6} \times 100 = 16.67 \% \).
Key Points
- > Formula for reduction \( = \frac{R}{100+R} \times 100 \)
- > Here \( R = 20 \)
- > Percentage calculation is always based on the new price
Additional Information
- Such problems are very important for competitive exams.
- If the price had decreased, the formula for increase would be \( \frac{R}{100-R} \times 100 \).
- It is convenient to remember the mathematical constant \( \frac{1}{6} = 16.67 \% \).
| Condition | Formula |
|---|---|
| Price Increase | \( \frac{R}{100+R} \times 100 \) |
| Price Decrease | \( \frac{R}{100-R} \times 100 \) |