(2) You are playing the computer game Civilization III designed by Sid Meir. In this game you are managing a medieval army. You are tasked with transporting soldiers from their 2 barracks to 3 castles located in the area.

Each barrack has the following number of soldiers

Barrack A : 515

Barrack B : 350

Each castle needs the following number of soldiers in order to maintain an effective defense

Castle X: 180

Castle Y:260

Castle Z: 230

The cost of transporting a soldier from one location to the next (in gold coins) is given below

	Castle X	Castle Y	Castle Z
Barrack A	5	4	2
Barrack B	3	6	7
Castle X	NA	2	NA
Castle Y	2.5	NA	3.5
Castle Z	1.5	4.5	NA

a) Draw the network

b) Formulate a model that will minimize cost

Hint: This is a trans-shipment problem. Have a look at the problems in the Network Models folder