Question 810724
The shorter measurement side should use the more expensive fence material.  Let {{{w<L}}} and the dimensions are w and L.


{{{2w+2L=220}}} and {{{14*w+6*w+2*L*6=c}}}, where c = cost.


Simplify the c equation.
{{{(14+6)w+12L=c}}}
{{{c=20w+12L}}}

Solve the perimeter equation for either variable.
w+L=110
L=110-w
Substitute into the c equation.
{{{c=20w+12(110-w)}}}
{{{c=20w+12*110-12w}}}
{{{c=8w+1320}}}


The description of the problem is missing something.