Question

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

Answer 1

depth of river = 3m
width of river = 40m
distance covered in 1 hour =2km= 2000m
total water falls in sea in 60 min = 40×3×2000=
240000 m3
total water falls in sea in 1 minute= 240000/60=4000m3 = 4000000 L

Answer 2

area = length x width
       (3x40)m2=120m2 
1km=1000m                                                              1000/60-=
2km- ?
2000m2 =2hours 
1000000m2=?
1,000,000 x2/2000= 1,000hrs

1 hr=60 min
1000hr=  1,000x60= 60,000.

1km2=1000x1000=1,000,000 m2
if 1 hr=60 minutes