Question 775460
a sheet of paper 20in. wide by 15in. high.
 He then places this sheet on a mat so that a uniformly wide strip of the mat shows all around the picture.
 The perimeter of the mat is 102 inches.
 How wide is the strip of mat around the picture?
:
Let x = the width of the strip
Then the mat will be: (2x+20) by (2x+15)
:
The perimeter
2(2x+20) + 2(2x+15) = 102
simplify, divide both sides by 2
(2x + 20) + (2x + 15) = 51
4x + 35 = 51
4x = 51 - 35
4x = 16
x = 16/4
x = 4 in the width of the strip