I need help on this ?/

What could explain what happened when the time was equal to 120 minutes

Divide. write in the simplest form. 4 1/6 divided by 10

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.