1.) We can set up a triangle. His velocity of 2 km/h is the hypotenuse of the triangle and the current's velocity of 1 km/h is the opposite height. Thus the angle we're looking for is

2.) The 15 degrees is the direction of the vectors and the 12 m/s and 5 m/s are the magnitudes of the vectors. If you draw out the vectors, you will see that they intersect at a right angle. Thus, using the "tip-to-tail" method of adding vectors is just the Pythagorean Theorem: . So it is going 13 m/s. To find its angle with the origin, you need to start by taking . However, this gives you the one of the angles of the 5-12-13 triangle, not the angle the 13 m/s vector makes with the origin. To find this angle, subtract from the angle you found above to get . So the boat travels at13 m/s in the direction east of north.

I'm sure that was confusing but if you draw out the picture it should be easier to understand.