KöMaL 2017 C1407

In a parallelogram $ABCD$, $M$ and $N$ are points on sides $AD$ and $DC$, respectively, such that $\frac{AM}{MD}=\frac{DN}{NC}=\frac{7}{11}$. Let $P$ denote the intersection of lines $BM$ and $AN$. Prove that the areas of triangle $APB$ and quadrilateral $DMPN$ are equal.