A local fumiture company recently began selling a newly designed bookshell. The amount of time t needed to assemble the bookshelf varies inversely with the number of people p working,
Three people assembled the bookshell in 45 minutes.
Provide an equation to model the inverse variation

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.