Two automobiles, each of mass 1000 kg, are moving at the same speed, 20 m/s, when they

Question:

Two automobiles, each of mass 1000 kg, are moving at the same speed, 20 m/s, when they collide and stick together. In what direction and at what speed does the wreckage move
(a) If one car was driving north and one south;
(b) If one car was driving north and one east?