Please solve the following questions!

How to use order of operation in 20 divide by 4 multiply 5 = 1

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.

Mrs. sling bought a pound of green beans for $1.80. how much will mrs. tennison pay for 3 1/2 pounds of green beans?