<PRE><B>Question 341313</B>
The perimeter formula is:


P = 2w + 2L


The width is: w = L/3


So take the w =L/3 and substitute it into the perimeter formula:


P = 2w + 2L
40 = 2(L/3) + 2L
40 = 2L/3 + 2L
40 = 2L/3 + 6L/3
40 = 8L/3
120 = 8L
L = 15


So length = 15 cm.

Width = Length/3
Width = 15/3 = 5 cm.</PRE>