A contrution crew is legthening a road that originally mesured measured 42 miles. the crew is adding one mile to tye road each day. The length L in miles after D days of contruction lis given by the following. L=42+d. What is the length of the road after 24 days

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.