the perimeter of a rectangle is all sides added up, so length + length + width + width.
L = length
W = width
then the perimeter is L+L+W+W, or 2L + 2W, or 2(L+W).
[tex]\bf \textit{perimeter of a rectangle}\\\\
P=2(L+W)~~
\begin{cases}
P=162\\
L=\stackrel{\textit{twice W}}{2W}
\end{cases}\implies 162=2(2W+W)
\\\\\\
\cfrac{162}{2}=3W\implies 81=3W\implies \cfrac{81}{3}=W\implies 27=W[/tex]
what's the length? well, is just 2(27).