$8-23($Airline fuel problem$)$ Coast$-$to$-$Coast Airlines is investigating the possibility of reducing the cost of fuel purchases by taking advantage of lower fuel costs in certain cities. Since fuel purchases represent a substantial portion of operating expenses for an airline, it is important that these costs be carefully monitored. However, fuel adds weight to an airplane, and, consequently, excess fuel raises the cost of getting from one city to another. In evaluating one particular flight rotation, a plane begins in Atlanta, flies from Atlanta to Los Angeles, from Los Angeles to Houston, from Houston to New Orleans, and from New Orleans to Atlanta. When the plane arrives in Atlanta, the flight rotation is said to have been completed, and then it starts again. Thus, the fuel on board when the flight arrived in Atlanta must be taken into consideration when the flight begins. Along each leg of this route, there is a minimum and a maximum amount of fuel that may be carried. This and additional information are provided in the table on the following page.

The regular fuel consumption is based on the plane carrying the minimum amount of fuel. If more than this is carried, the amount of fuel consumed is higher. Specifically, for each $1,000$ gallons of fuel above the minimum, $5\%($or $50$ gallons per $1,000$ gallons of extra fuel$)$ is lost due to excess fuel consumption. For example, if $25,000$ gallons of fuel are on board when the plane takes off from Atlanta, the fuel consumed on this route will be $12+0\mathrm{.}05=12\mathrm{.}05$ thousand gallons. If $26,000$ gallons are on board, the fuel consumed will be increased by $0\mathrm{.}05$ thousand, for a total of $12\mathrm{.}1$ thousand gallons.

Formulate this as an LP problem to minimize the cost. How many gallons should be purchased in each city? What is the total cost of this?

$\backslash$table$[[\backslash$table$[[$Data for$],[$Problem $8\mathrm{.}23]],$LEG,$\backslash$table$[[$MINIMUM FUEL$],[$REQUIRED$],[(1,000$ GAL.$)]],\backslash$table$[[$MAXIMUM FUEL$],[$ALLOWED$],[(1,000$ GAL.$)]],\backslash$table$[[$REGULAR FUEL$],[$CONSUMPTION$],[(1,000$GAL$).]],\backslash$table$[[$FUEL PRICE PER$],[$GALLON$]]],[,$Atlanta$-$Los Angeles,$24,36,12,$$$4\mathrm{.}15$