Question 320086
{{{P=2L+2W<150}}}
{{{L+W<75}}}
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.
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Let {{{W=x}}}
Then,
{{{L=4x}}}
Substituting,
{{{4x+x<75}}}
{{{5x<75}}}
{{{highlight(x<15)}}} cm
On the other side, 
{{{x>0}}} cm
So then put together this yields,
{{{highlight_green(0<x<15)}}} cm