Question

please help ..You and your friends are doing physics experiments on a frozen pond that serves as a frictionless, horizontal surface. Sam, with mass 72.0 kg, is given a push and slides eastward. Abigail, with mass 59.0 kg, is sent sliding northward. They collide, and after the collision Sam is moving at 31.0^\circ north of east with a speed of 6.00 m/s and Abigail is moving at 21.0^\circ south of east with a speed of 9.40 m/s. find same speed