Question

A river 1.5 m deep and 36 m wide is flowing at the rate of 3.5 km/hr. Find the amount of water (in cubic metres) that runs into the sea per minute.

Answer 1

First change the rate of flow of water of the river in metre/min.

Since 1 km=1000 m
and 1 hour=60 minutes, we have
3.5 km per hour=3.5 km/1 hour
=3.5×1000 m/1×60 min
=350/6 m/minThis means that in 1 min, the river travels 350/6 m
Further, It is given that the river is 1.5m deep and 36 m wide.
So the amount of water than runs into the sea per minute will be
350/6 $\times$1.5 $\times$36

=350 $\times$1.5 $\times$6
=3150 Thus the required amount of water is 3150 $m^3$/min