Hello candidate,

In 1D collision, the collision always happens in one direction and is of elastic nature due to which there is a conservation of internal kinetic energy and momentum.

So, total momentum before collision= total momentum after collision. Moreover, total kinetic energy before collision= total kinetic energy after collision. Since the mass add initial velocity of the bodies are not certain in this question, so it's not possible to get the direct value of final velocities from this insufficient information (the number of unknown variables are more than the number of equations available).

But using momentum conservation and kinetic energy conservation theorems, finding the initial masses and initial velocities of both bodies, the problem can be solved very easily by just equating two equations and finding out respective values.

Have a good day.