Given point P(4, 1, -5) and point Q(1, 7, -14). Point R is

Given point P(4, 1, -5) and point Q(1, 7, -14). Point R is the line PQ, so PR=1/3 PQ.a. Find a vector which representing the directed line PQ.b. Find a vector is represented by a directed line PR.c. Find coordinat point R.