Simple boat and river question(Vectors)

[dmitrip]

Homework Statement

In his rowboat, Pierre heads directly across a river at a speed of 10 km/h. The river is 120m wide and is flowing at 6 km/h.

Suppose Pierre wants to row directly across the river. At what angle relative to the shore should he head?

I would really appreciate help with this question, since I know that it is suppose to be straight forward and for some reason I just can't solve it! must be because I didn't have much of a sleep.

thanks a lot

 

[AFG34]

Vbg = Vbw + Vwg
where Vbg is the velocity of the boat relative to the ground, Vbw is the velocity of boat relative to water, Vwg is the veloctiy of the water relative to the ground.