The Washimore County Transportation Commission is planning to develop a road system

linking City $1$ to City $9($see figure$).$ Two proposals are under consideration:

A series of six$-$lane super$-$streets linking all $9$ cities. Super$-$streets are estimated to

cost $$600,000$ per mile to build.

A ten$-$lane freeway extension connecting City $1$ with City $9($which does not neces$-$

sarily pass through all nine cities.$)$ Each mile of the freeway will cost $$800,000.$

Both proposals will implement a minimum cost solution. Based on cost alone which

proposal should be implemented? Justify your answer. $($Figures next to arc $(i,j)$ is the

mileage from $i$ to $j.)$