A farmer has a rectangular tank with base area 10 square metres. Rain falls uniformly at 20 mm per day. The tank’s capacity is 1000 litres. How many days will it take to fill the tank completely?
Answer
5 days
The correct answer is 5 days — Number of days = 1000 ÷ 200 = 5 days.
Step-by-step solution
- Convert rainfall depth from millimetres to metres: 20 mm = 0.02 m.
- Find volume of rainwater falling on one square metre: 1 m² × 0.02 m = 0.02 m³.
- Since tank area is 10 m², volume per day = 10 × 0.02 = 0.20 m³.
- Convert cubic metres to litres: 0.20 m³ = 200 litres.
- Total capacity of tank = 1000 litres.
- Number of days = 1000 ÷ 200 = 5 days.
Common mistake: Using millimetres directly as volume or forgetting unit conversion
Concept tested: Rainfall volume calculation
Published · How this solution was prepared and checked
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