1. The problem statement, all variables and given/known data Particle X moves with a velocity of 15 m/s[R]. Particle Y moves with a velocity of 5.0 m/s[L]. What is the velocity of particle X with reference to particle Y? The correct answer is 20 m/s (R). I do not understand what velocity in reference to particle Y means, and how to find it. 2. Relevant equations d= (vi)t + 1/2 at^2 (vf)^2= (vi)^2 + 2ad vf= vi + at a=(vi+vf)/2 X t 3. The attempt at a solution I have drawn the vectors ( not sure if correctly done), but i do not know what my next step is.