Consider the network below. Formulate the LP model for finding the shortest-route path from node 1 to node 7. Consider the arcs between the transnodes (2-6) as two-way and travel times are shown on the arcs.

Please indicate the model first (objective function and the constraints) below then place into LINDO for optimal solution. Indicate the shortest-route path and objective value (distance) below. Show all work for credit.

Hint: The objective function starts with:

MIN 21x12 + 18x13 + 13x24 + ...