Question 946121
{{{W=4D}}}
Six years ago,
{{{(W-6)(D-6)=136}}}
Substituting,
{{{(4D-6)(D-6)=136}}}
{{{4D^2-30D+36=136}}}
{{{4D^2-30D-100=0}}}
{{{2D^2-15D-50=0}}}

{{{(D-10)(2D+5)=0}}}
Only the positive solution makes sense.
{{{D-10=0}}}
{{{D=10}}}
So then,
{{{W=4(10)}}}
{{{W=40}}}