David is building a wooden picture frame. each frame requers 3/4 feet of wood. If david started with 12 feet and now has 6 feet remaining. How many picutre frames did he build.

An appliance store sells a washer-dryer combination for $1800. if the washer costs $300 more than the dryer, find the cost for each appliance.

Michael is training for a marathon. in his first week he plans to run 8miles. what path should he take

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.