Geometry Essentials · Medium problem

Rays $\overrightarrow{OB}$ and $\overrightarrow{OC}$ lie in the interior of $\angle AOD$. If $m\angle AOD = 140^\circ$, $m\angle AOB = 40^\circ$, and $m\angle COD = 50^\circ$, find $m\angle BOC$.