Question

A boatman can row with a speed of 10km/h in still water. If the river flows at 5km/h, in which direction should boat man will row in water to reach a point on the other bank directly opposite to point from where he started width of river 2km

Answer 1

For reaching the bank right opposite the swimmer have to swim with some angle with vertical 

So the components will be balanced 

  V(swimmer) cosx = v(river)

 cosx = 5/10

x=30 degree with vertical from where the river flows OR

 60 degree with bank towards the direction from where the river flows

Answer 2

Hope you have received your answer...