After 100 draws, Ana picked a pink shirt 20 times. Based on the probability, if she knows there are 5 shirts in the drawer, how many shirts would she expect to be pink?

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.