Question $3$: Three refineries with daily capacities of $12,10,$ and $16$ million gallons, respectively, supply

three distribution areas with daily demands of $8,16,$ and $14$ million gallons, respectively. Gasoline is

transported to the three distribution areas through a network of pipelines. The transportation cost is $20$

cents per $1000$ gallons per pipeline mile. Below is the mileage chart. Refinery $1$ is not connected to