Depends upon the situation. If you are talking about two objects with the same mass colliding then set up energy before and after the collision and use the conservation of mechanical energy. You should find velocity is completely independent of mass in this case.
Does this help?
yes it does help somewhat. That said however could you give a more in depth explanation if possible. And also in a situation whereby one mass(m1) moving down an incline collides with another mass(m2). One other question regarding the previous situation too if m1 was greater than m2 would velocity still be independent.
Well I can't really get any more in depth than that. I assume you know the equation for kinetic energy?
As far as the second situation goes: ignoring friction then what you need to do is work out how the velocity changes due to gravitational acceleration as the ball moves down the incline. This should give you your velocity when it hits the other ball. Once you have that you may be able to use the conservation of energy to calculate the final velocities.
If I remember my mechanics correctly the final velocities in a collision should only depend upon mass if the masses are equal (assuming conservation of mass of course).