A point C with position vector $\frac{3\overline{\mathrm{a}}+4\overline{\mathrm{b}}-5\overline{\mathrm{c}}}{3}$ (where $\overline{\mathrm{a}}, \overline{\mathrm{b}}$ and $\overline{\mathrm{c}}$ are non coplanar vectors) divides  the  line  joining A and B in the ratio 2 : 1. If the position vector of A is $\overline{\mathrm{a}}-2\overline{\mathrm{b}}+3\overline{\mathrm{c}},$ then the position vector of B is