An airline, all of whose planes fly with an airspeed of 300 km/h, serves three cities, A, B, and C, where B is 400 km due east of A, and C is 400 km due north of A. On a certain day there is a steady wind of 150 km/h from the east. (a) Find the time needed for a round trip from A to B and back. (b) Find the time needed for a round trip from A to C and back