Solve each part of given question:
Question: An airplane pilot wishes to fly due west. A wind of 74.0km/h is blowing toward the south.
Part A: If the airspeed of the plane (its speed in still air) is 450.0km/h, in which direction should the pilot head?
Part B: What is the speed of the plane over the ground?
Please show your results in detailed calculations for above question.