Verified answer

Does it give you any more information? Like the boats velocity?

Because the river has a current, which is 5.0km/h [east or west]

then you have the boats velocity going north.

so you have the X and Y components, and if you join them, they make a right triangle. from there you can use pythagorean, and get the hypotenuse (resultant) then inverse tangent to get the angle!