A rancher is mixing two types of foods, Brand X and Brand Y, for his cattle .each serving for cattle is required to have 360 gram of protein and 360 grams of fat. brand x has 5 grams of protein and 10 gram of fat. Brand Y has 10 gram protein and 5 gram of fat.Rancher has found that brand x cost $3.5 and brand y cost $5 per unit. find out how much of each type should be used by rancher to minimize the cost? keep in mind that the rancher has to buy at least one unit of each brand. moreover , the number of brand X has to be twice the number of brand Y.