Question 1103848
For a rectangle,
{{{P=2L+2W}}}
So,
{{{2L+2W=124}}}
{{{L+W=62}}}
and
{{{L=6+3W}}}
Substituting,
{{{(6+3W)+W=62}}}
{{{4W=56}}}
{{{W=14}}}{{{cm}}}
Now use either of the equations to solve for {{{L}}}.