Given: A river is flowing at the rate of 2 km/hr Depth and width of the river are 3 m and 40 m respectively Concept used: The amount of water flow will be equal to the volume of the river Calculation: 2 km/hr = 2000 m/60 minute ⇒100/3m/min. The volume of water that falls into the sea in a minute =3m×40m×(100/3)m ⇒4000m3 ∴ The amount of water that falls into the sea in one minute is 4000m3