Christopher invested $9,800 in an account paying an interest rate of 2 5/8% compounded quarterly. Avery invested $9,800 in an account paying an interest rate of 2 1/4% compounded annually. To the nearest hundredth of a year, how much longer would it take for Avery's money to triple than for Christopher's money to triple?

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.