Two identical balls A and B having velocities of 0.5 m/s and -0.3 m/s respectively collide elastically in one dimension. The velocities of B and A after the collision respectively will be?

On elastic collision between two masses moving with finite velocities, their velocities get exchanged and they travel in opposite directions as they were initially.Hence the velocity of B is +0.5m/s and that of A is -0.3m/s