(a) If a particle that is moving has the same momentum and the same kinetic energy as another, must their masses and velocities be equal? If so, explain why, and if not, give a counterexample. (b) Describe the properties of two particles that have the same momentum, but different kinetic energies.

I got the answer to be the velocity and masses has to be equal, but apparently the answer is that they don't have to be equal. Can someone explain? Thanks