Two passenger trains are passing each other on adjacent tracks. Train A is moving east with a

Question:

Two passenger trains are passing each other on adjacent tracks. Train A is moving east with a speed of 13 m/s, and train B is traveling west with a speed of 28 m/s.
(a) What is the velocity (magnitude and direction) of train A as seen by the passengers in train B?
(b) What is the velocity (magnitude and direction) of train B as seen by the passengers in train A?