A rooftop of 6 sq m receives 35 mm rainfall in one day. If 65% of the rainwater can be collected in a bucket, how many litres of water can be collected?

Step-by-step solution

1. Convert rainfall depth to metres: $35\text{mm}=0.035\text{m}$.
2. Compute volume in cubic metres: $V=0.035\text{m}\times 6{\text{m}}^2=0.21{\text{m}}^3$.
3. Convert to litres: $0.21\times 1000=210\text{L}$.
4. Apply 65% collection: $210\times 0.65=136.5\text{L}$.

Concept tested: Rainwater harvesting calculation

Published 16 October 2026 · How this solution was prepared and checked