At a special sale, all pens are sold at one price and all pencils at another price. If 3 pens and 2 pencils are sold for $0.47 (forty-seven cents) while 2 pens and 3 pencils are sold for $0.38 (thirty-eight cents), what is the cost of a set of one pen and one pencil in cents?

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.