Position vector of P= 3→a−2→b
Position vector of Q= →a+→b
Point R divides segment PQ in ratio 2:1 externally.
Position vector of R= (Position of P)1−(Position of Q)21−2
Position vector of R= (3→a−2→b)1−(→a+→b)2−1=→a−4→b−1
Therefore, position vector of R= 4→b−→a.