A manufacturer produces three models $($I$,$ II and III$)$ of a certain product. He uses two types of raw materials $($ A and B$)$ of which $4,000$ and $6,000$ units, respectively, areavailable. The raw material requirements per unit of the three models are as follows: The labour time of each unit of model I is twice that of model II and three times that of model III. The entire labour force of the factory can produce equivalent of $2,500$ units of model I. A market survey indicates that the minimum demand of the three models is: $500,500$ and $375$ units, respectively. Assume that the profit per unit of models I, II and III are $60,40$ and $100$ euro, respectively. Formulate this problem as an LP model to determine the number of units of each product which will

maximize profit.