A river 3 m deep and 40 m wide is flowing at the rate of 2 km per hour. How much water will fall into the sea in a minute.

Given that ,

                 Depth of the river = 3 m

                 Width of the river = 40 m

                  And rate of flow the river = 2 km/h

 Now we have to find length of the river .

So, Length of the river =  distance travelled by water in 1 minutes at speed 2km/h $=\frac{2000}{60}=\frac{100}{3} m$

So, volume of the water $=\frac{100}{3}\times 40\times 3=4000 {\mathrm{m}}^{3 }=4000000 \mathrm{litre} \left[1 {\mathrm{m}}^{3 }=1000 \mathrm{litre}\right]$