three spheres of mass 1kg,2kg and 3kg move in the same line with velocities 5i,i and 3i respectively. the smaller masses are the first to collide.if only one collision takes place find the maximum value for the coefficient of restitution between the smaller masses.

what ive got so far: 5(1)+1(2)=1(x)=2(y) using the law of conservation of momentum. 7=x+2y

using law if restitution -e=x-y/5-1 -4e=x=y

i also know y>x as there no more collisions. y>3 also if there are no more collisions.