Question 889573
Let w = width and L = length.
{{{L=2w-5}}} and {{{50>2w+2L>36}}}.


Wanting the longest length, first solve for w in terms of L.
{{{2w=L+5}}}
{{{w=(L+5)/2}}}, and substitute this into the inequality.


{{{50>2(L+5)/2+2L>36}}}
{{{50>L+5+2L>36}}}
{{{50>3L+5>36}}}
{{{50-5>3L>36-5}}}
{{{45>3L>29}}}
{{{29/3<L<45/3}}}
{{{highlight(29/3<L<15)}}}


For the LONGEST possible rectangle, L can be <s><s>as near to 15 as desired but still must be less than</s></s> 15.  A suitable value for w can then be found in order to agree with the inequality.