Question 906766
the equation for perimeter is p = 2L + 2w. If you let w represent the width, then you can make the equation: 
(166) = 2(3w-13) + 2(w)

then isolate w

166 = 6w - 26 + 2w
192 = 8w
24 = w
 
Therefor, the width is 24inches