Use northwest$-$corner method to find the starting solution. Develop iterations that lead to the optimal solution.

Table $1$: Costs for Problem $1$

$\backslash$table$[[,$Area $1,$Area $2,$Area $3,$Supply$],[$Refinery $1,0,2,1,6],[$Refinery $2,2,1,5,9],[$Refinery $3,2,4,3,5],[$Demands$,5,5,10,]]$