Josslyn has dimes and one dollar bills in her pocket. The number of dimes is three less than six times the number of one dollar bills. Let o represent the number of one dollar bills. Write an expression for the number of dimes

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.