Your bedroom wall is 221 inches wide. You want to hang two posters, each 28 inches across, with an equal space between each poster and the wall edges. How many inches of space should you leave between the wall edge and each poster?

221-28-28=165 (space left after hanging two posters)

165/4 because there will be 4 spaces in total between the wall edge and each poster

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm