Last season two running backs on the steelers football team rushed or a combined total of 1550 yards. one rushed 9 times as many yards as the other. how many yards were rushed by each player?

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.