On monday, it took helen three hours to do a page of science homework exercises. the next day she did the same number of exercises in two hours. if her average rate on monday was p exercises per hour, what was her average rate the next day, in terms of p?

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.