Troy has $8.50 in his bank account and his sister shea has -$13.00 in her bank account. use the space below to explain, in words or pictures, the amount of money each person has in their account. also explain what it means to have an account balance of $0.

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.