for #2.
(A) The resultant velocity of the boat is the hypotenuse of a right triangle with the sides being the river and boat velocities.
The Pythagorean theorem: h^2 = a^2 + b^2
then you can use: soh cah toa to find any angles.
(B) The river velocity is not opposing the direction of travel, it increases the boats velocity from 2m/s to 2.5m/s
