<image> As shown in the figure, in rectangle $$ABCD$$, $$BC=20cm$$. Points $$P$$ and $$Q$$ start from points $$B$$ and $$D$$, respectively, moving counterclockwise along the edges of rectangle $$ABCD$$. The speeds of points $$P$$ and $$Q$$ are $$3cm/s$$ and $$2cm/s$$, respectively. The shortest time after which quadrilateral $$ABPQ$$ becomes a rectangle is ______ $$s$$.