Questions : The price of sugar increases from ₹20/kg to ₹30/kg. By what percent consumption must be decreased to maintain the same expenditure?
Answer:
Step 1: Calculate the Percentage Increase in Price
The price increases from ₹20/kg to ₹30/kg, so the percentage increase is:
Step 2: Apply the Shortcut Formula
Final Answer
The consumption must be decreased by 33.33% to maintain the same expenditure.
Additional Methods
Here's how to calculate the percentage decrease in consumption needed to maintain the same expenditure:
1. Understand the relationship:
- Expenditure = Price * Consumption
2. Set up the equation:
Let:
- P1 = Original price (₹20/kg)
- C1 = Original consumption (unknown)
- P2 = New price (₹30/kg)
- C2 = New consumption (unknown)
Since the expenditure remains the same:
P1 * C1 = P2 * C2
3. Solve for the ratio of consumptions:
20 * C1 = 30 * C2
C1 / C2 = 30 / 20
C1 / C2 = 3 / 2
This means the original consumption (C1) was 3/2 times the new consumption (C2).
4. Calculate the percentage decrease:
- Decrease in consumption = C1 - C2
- Percentage decrease = (Decrease in consumption / Original consumption) * 100
- Percentage decrease = ((C1 - C2) / C1) * 100
Substitute C1 = (3/2) * C2:
Percentage decrease = (((3/2) * C2 - C2) / ((3/2) * C2)) * 100
Percentage decrease = ((1/2) * C2 / (3/2) * C2) * 100
Percentage decrease = (1/3) * 100
Percentage decrease = 33.33% (approximately)
Answer: The consumption must be decreased by approximately 33.33% to maintain the same expenditure.
