A school in Delhi has a roof area of 250 m². The average monsoon rainfall is 850 mm and the runoff coefficient for the roof is 0.85. Calculate the maximum volume of rainwater (in cubic metres) that can be harvested from the roof during the monsoon season.
Answer
180.63 m³ (approximately)
The correct answer is 180.63 m³ (approximately) — Round the result to two decimal places: 180.63 m³.
Step-by-step solution
- Convert rainfall from millimetres to metres: 850 mm = 0.85 m.
- Calculate the theoretical volume without loss: 250 m² × 0.85 m = 212.5 m³.
- Apply the runoff coefficient to account for losses: 212.5 m³ × 0.85 = 180.625 m³.
- Round the result to two decimal places: 180.63 m³.
Common mistake: Forgetting to convert mm to metres or ignoring runoff coefficient
Concept tested: Rainwater harvesting calculation
Published · How this solution was prepared and checked
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