Packages in an automobile parts supply house are transported to the loading dock by pushing them along

Question:

Packages in an automobile parts supply house are transported to the loading dock by pushing them along a roller track with very little friction. At the instant shown packages B and C are at rest and package A has a velocity of 6 ft/s. Knowing that the coefficient of restitution between the packages is 0.3, determine

(a) The velocity of package C after A hits B and B hits C,

(b) The velocity of A after it hits B for the second time.