Let O be the origin, OP→=a→\overrightarrow{OP}=\overrightarrow{a}OP=a and OQ→=b→\overrightarrow{OQ}=\overrightarrow{b}OQ=b. If R is the point on OP→\overrightarrow{OP}OP such thatOP→=5OR→\overrightarrow{OP}=5\overrightarrow{OR}OP=5OR, and M is the point such that OQ→=5RM→\overrightarrow{OQ}=5\overrightarrow{RM}OQ=5RM, then PM→\overrightarrow{PM}PM is equal to :
15(a→−4b→)\;\dfrac{1}{5}(\overrightarrow{a}-4\overrightarrow{b})51(a−4b)
15(b→−4a→)\;\dfrac{1}{5}(\overrightarrow{b}-4\overrightarrow{a})51(b−4a)
15(−a→+4b→)\;\dfrac{1}{5}(-\overrightarrow{a}+4\overrightarrow{b})51(−a+4b)
15(−b→+4a→)\;\dfrac{1}{5}(-\overrightarrow{b}+4\overrightarrow{a})51(−b+4a)