M(4,5) is the midpoint of line rs. The coordinates of s are (6,7). What are some coordinates of R

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.

Ibeg you to me 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?

Akayaker travels 3 miles upstream and 3 miles downstream in a total of 4 hours. in still water, the kayaker travels at a speed of 2 mph. what is the average speed of the river's current?