What is all of the factors of 13

What is the common denominator for 3/5+3/4

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.

You are saving to buy a bicycle; so far you save 55.00. the bicycle costs 199.00. you earn 9.00 per hour at your job. which inequality represents the possible number of h hours you need to work to buy the bicycle?