Olympiad Geometry · Hard problem

Horizontal lines $\ell$ and $m$ are parallel, with $\ell$ above $m$. Point $A$ is on $\ell$, point $B$ is on $m$, and point $P$ lies between the two lines, to the right of both $A$ and $B$. Point $Q$ is on $\ell$ to the right of $A$, and point $R$ is on $m$ to the right of $B$. If $m\angle QAP = (2x + 10)^\circ$, $m\angle RBP = (3x - 4)^\circ$, and $m\angle APB = 96^\circ$, find $m\angle RBP$.