Asubmarine dives to a depth of 54.6 meters below the surface of the water in 4 minutes. what integer represents the constant rate the submarine travels per minute? i need work with the answer to. step by step

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.