$\overrightarrow {{\text{QP}}}$;

$\overrightarrow {{\text{OT}}}$.

appropriate approach     (M1)

eg     $\overrightarrow {{\text{QP}}}  = \overrightarrow {{\text{QO}}}  + \overrightarrow {{\text{OP}}} ,{\text{ P}} - {\text{Q}}$

$\overrightarrow {{\text{QP}}}$ = p – q     A1     N2

[2 marks]

recognizing correct vector for $\overrightarrow {{\text{QT}}}$ or $\overrightarrow {{\text{PT}}}$     (A1)

eg     $\overrightarrow {{\text{QT}}}  = \frac{1}{2}$(p – q), $\overrightarrow {{\text{PT}}}  = \frac{1}{2}$(q – p)

appropriate approach     (M1)

eg     $\overrightarrow {{\text{OT}}}  = \overrightarrow {{\text{OP}}}  + \overrightarrow {{\text{PT}}} ,{\text{ }}\overrightarrow {{\text{OQ}}}  + \overrightarrow {{\text{QT}}} ,{\text{ }}\overrightarrow {{\text{OP}}}  + \frac{1}{2}\overrightarrow {{\text{PQ}}}$

$\overrightarrow {{\text{OT}}}  = \frac{1}{2}$(p + q)   $\left( {{\text{accept }}\frac{{p + q}}{2}} \right)$     A1     N2

[3 marks]