InterviewSolution
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Water tax is increased by 20% but its consumption is decreased by 20%. Then the increase or decrease in the expenditure of the money is1. 5% increase 2. 5% decrease3. 4% increase 4. 4% decrease |
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Answer» Correct Answer - Option 4 : 4% decrease Given: Water tax is increased by 20% but its consumption is decreased by 20%. Calculations: Let the expenditure of water consumption be Rs. y and the tax imposed is x%. so the tax needs to be paid = Rs. (x/100) × y = Rs. xy/100 Now new tax = (x × 120/100)% = (6x/5)% and new expenditure = Rs. y × 80/100 = Rs. 4y/5 new tax = Rs. (6x/500) × 4y/5 = Rs. 24xy/2500 so change in tax = xy/100 - 24xy/2500 = xy/2500 then percentage change = (change/original) × 100 ⇒ \(\frac{\frac{xy}{2500}}{\frac{xy}{100}}\ ×\ 100\ = \) (1/25) × 100 = 4% decrease (since new tax is less than original tax) ∴ The correct answer is 4%. Short Tricks: 1.2 × 0.8 = 0.96 = 96 % (4 % decrease from original) |
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