Let $$ABCDE$$ be a convex pentagon with $$AB || CE, BC || AD, AC || DE, \angle ABC=120^\circ, AB=3, BC=5,$$ and $$DE = 15.$$ Given that the ratio between the area of triangle $$ABC$$ and the area of triangle $$EBD$$ is $$m/n,$$ where $$m$$ and $$n$$ are relatively prime positive integers, find $$m+n.$$

(第二十二届AIME2 2004 第13题)