`BC` is divided into four equal parts by `P,Q` and `R`.The resultant of `vec(AB)` and `3vec(AC)` is

Options

A. `vec(AR)`
B. `4vec(AR)`
C. `4vec(AP)`
D. `vec(PQ)`

Answer

B

Explanation

`vec(AC)+vec(CB)=vec(AB),vec(AC)+vec(4CR)=vec(AB)`
`vec(AC)+vec4((AR)-vec(AC)),vec4(AR)-3vec(AC)=vec(AB)`
`:.vec(AB)+3vec(AC)=4vec(AR)`