Lesson eLearning

An Indian town generates 500 kg of solid waste per day. A new segregation and composting programme reduces the amount of waste sent to landfill by 10% each year. What is the amount of waste that will be sent to landfill at the end of 3 years? Round to the nearest kilogram.

medium 3 marks Class 10 · Science · Our Environment
Answer
365 kg per day

The correct answer is 365 kg per day — State the answer.

Step-by-step solution

  1. Let W0 = 500 kg/day be initial waste sent to landfill.
  2. Each year the waste is reduced by 10%, so multiplier = 0.9.
  3. After year 1, W1 = W0 × 0.9 = 500 × 0.9 = 450 kg/day.
  4. After year 2, W2 = W1 × 0.9 = 450 × 0.9 = 405 kg/day.
  5. After year 3, W3 = W2 × 0.9 = 405 × 0.9 = 364.5 kg/day.
  6. Round 364.5 to nearest kg → 365 kg/day.
  7. State the answer.
Common mistake: Using cumulative 10% reduction instead of compound reduction

Concept tested: Reduction in landfill waste

Published · How this solution was prepared and checked

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