Olympiad Geometry · Hard problem

Parallel lines $\ell$ and $m$ are cut by a transversal $t$ at point $A$ on $\ell$ and point $B$ on $m$. On the same side of $t$, the two interior angles measure $(4x + 6)^\circ$ at $A$ and $(6x - 16)^\circ$ at $B$. The bisectors of these two angles meet at point $P$ between the lines. Find $m\angle ABP$.