The distance traveled at a constant speed is directly proportional to the timeof travel olivia traveled 306 milesin 8.5 hours, how many miles will olivia travel in 9.1 hours at the same constant speed

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.