Drew received a bonus check for $2500 and he's going to deposit the money into a bank account there is is 5.5% simple interest amount of interest earned each year is how much

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.