Brian invests £1900 into a savings account. The bank gives 3.5% compound interest for the first 2 years and 4.9% thereafter. How much will Brian have after 6 years to the nearest pound?

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.