Q1. Tawaab earns an annual salary of £28500. a) A promotion comes up at work and his pay will increase by 7%. What is the pay increase? b) David earns the same as Tawaab before he decides to work part-time and his salary reduces to £23,370. What is the percentage change in his salary?

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.