Ramesh buys a pen for rs 20 and sells it at 20% profit for what price should he buy it so that he can make 25% profit by selling for the same selling price​

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.