Question 17
Points $A,B,C$ are collinear in that order. Equilateral triangles $ABD$ and $BCE$ lie on the same side of $AC$. A point $N$ on $BE$ satisfies $NE:NB=4:5$. Line $AN$ meets $BD$ at $M$ and $CE$ at $P$. If $AB=16$ and triangles $AMB,ENP$ have equal areas, find $BC$.
