Question

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

Answer 1

Speed of flowung water=2km/hr Distance travelled by water in 1 min=2×60=120km Volume of water flowing in river=volume of water covering distance of 2km =3×40×120×1000 =14400000m^3 =14400liters

Answer 2

given:  distance = 40 m = 40/1000 km
formula 
speed = distance / time taken
time = distance / speed
         = 40     x 1
            1000    2
         = 2/100 hr
         =  2     x 60 min
            100

         = 1.2 minutes
so, water will fall into the sea in 1.2 minutes