Question 1138603


{{{w+L=36/2}}}
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{{{w+2L=60/2}}}

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{{{system(w+L=18,w+2L=30)}}}


{{{L=30-18}}}


{{{highlight(L=12)}}}


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HOW?
Assign variables; choosing w for width and L for length.
Dimension sum shortcut related to perimeter:  {{{w+L=(1/2)p}}}, if p is perimeter.
Follow the description and write the equations.
Solve for the variables - I chose Elimination Method because it seemed very convenient.


You can finish and solve for w.