A family uses a washing machine that consumes 75 litres of water per wash. They wash clothes 5 times a week. If they decide to reduce water per wash by 20% by using a low‑water setting, what will be the total water consumption in a month (4 weeks) before and after the reduction, and what is the total water saved?
Answer
Before: 1500 litres, After: 1200 litres, Saved: 300 litres
The correct answer is Before: 1500 litres, After: 1200 litres, Saved: 300 litres — State results
Step-by-step solution
- Compute monthly wash count: 5 washes×4 weeks=20 washes
- Compute monthly consumption before reduction: 75 L/wash×20 washes=1500 L
- Calculate reduced water per wash: 75 L×(1−0.20)=60 L
- Compute monthly consumption after reduction: 60 L×20 washes=1200 L
- Find water saved: 1500 L−1200 L=300 L
- State results
Common mistake: Only reducing total consumption instead of per wash
Concept tested: Water savings from reduced usage
Published · How this solution was prepared and checked
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