Gisella works at the R. O.M. in a kiosk selling handmade bracelet. Her earnings are represented by the formula E = 11n + 2b, where E is her earnings in dollars, h is the
number of hours worked and b is the number of bracelets she sells.
How many bracelets must she sell to earn $105 in 7 hours?

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.