Let Width (inches) = X
Let Length (inches) = 3x + 2
40 = (x) + (3x + 2) + (x) + (3x +2)
40 = 8x + 4
-4 -4
36 = 8x
/8 /8
4.5 = x (width)
Length = 3x + 2
length = 3(4.5) + 2
length = 13.5 + 2
length = 15.5 inches
CHECK
40 = 15.5 + 4.5 + 15.5 + 4.5
40 = 20 + 20
40 = 40