A river 3 m deep and 40 m wide is flowing at the rate of 3 km/h. How much water will fall into the sea in 3 minutes?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \(18000\,\mathrm{m^3}\)
The water that reaches the sea in a given time is a block with the river's cross-section (depth × width) as its face and the distance the water flows in that time as its length.
Speed of the water: 3 km/h = 3000 m in 60 minutes = 50 m per minute
Distance the water flows in 3 minutes: \(50\times3=150\,\mathrm{m}\)
Volume: \(3\times40\times150=18000\,\mathrm{m^3}\)