I dont know how to slove it

4. (17 marks) An oil refinery produces two types of liquid fuels (A and B) by blending crude oils of two different grades (I and II) and certain additives (III). A and B are sold at $12 and $14 per gallon respectively. The costs of I, II and III are $7, $6 and $8.2 per gallon respectively. The table below shows availabilities of raw materials and various specifications. C1 There are 7,000 gallons of I available. There are 10,000 gallons of II available. There are 4,500 gallons of III available. CA At most 35% of A is I. At least 40% of A is II. 6 At most 10% of A is III. At least 25% of B is I. Ca I in B is no more than II in B. Co At most 30% of B is III. C10 A is at least 7,000 gallons due to a special demand The objective is to maximize the total profit. Let x1 denote the number of gallons of raw material j (j =I, II or III) used in the production of fuel i (i =A or B). (a) Find the objective function. Express your answer in Excel-ready form. (b) Write mathematical descriptions for constraints C1, C4 and C10. Express your answers with