Question

Two hockey players traveling at 12 m/s (Player #1) and 19 m/s (Player #2) hit in a head-on collision. They grab onto each other to keep from falling and slide in the same direction Player #2 was traveling at a speed of 5 m/s. Player #1 has a mass of 100 kg. What is Player #2’s mass?

So far I've tried to use the momentum equation:

m1v1 + m2v2 = (m1+m2) v'
(100)(12) + m2(-19) = (100 + m2) (-5)

But I keep getting the wrong answer based off my teacher's answer key.