Boat Crossing River - Vectors?

[MDwannabe7]

Okay, A boat can move with a speed of 20 m/s in still water. It starts at the shore of a river that flows at a rate of 10 m/s. In what direction must the boat move to reach the exact same point on the opposite shore?

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[HawkeyePostOp]

20 is the vector sum (hypotenuse). 10 is the adjacent direction.
inverse cosine(10/20) = 60 degrees from the direction of water flow.

This friday night needs a martini.

 

[MDwannabe7]

Hey thanks - seems simple when you put it that way, it's obviously been a while since I've been in Physics!