The St Louis Box Factory produces three grades (high, medium, and low) of boxes at two mills. Each mill has a different production capacity (in tons per day) for each grade, as follows:

	Mill 1	Mill 2
High Grade	5.8	2.2
Medium Grade	2.4	4.1
Low Grade	3.8	8.6

The company has contracted with a manufacturing firm to supply at least 10 tons of high-grade boxes, 8 tons of medium-grade boxes, and 6 tons of low-grade boxes. It costs the company $6,500 per day to operate mill 1 and $7,400 per day to operate mill 2. The company wants to know the number of days to operate each mill in order to meet the contract at the minimum cost.

Formulate a linear programming model for the above situation by determining

(a) The decision variables.

(b) Determine the objective function. What does it represent?

(c) Determine all the constraints. Briefly describe what each constraint represents.