Will mark eliza started her savings account with $100. each month she deposits $25 into her account. determine the average rate of change in eliza's account from the 2nd month to the 10th month. show all work for full credit.

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.