Need to build an Excel optimization model to find the mixture with lowest total cost!

The Blanton Seed Company specializes in food products for birds and other household pets. In developing a new cockatiel mix, company nutritionists have specified that the mixture must contain at least 13 percent protein and 15 percent fat, and no more than 15 percent fiber. Given in the table below are the percentages of each of these nutrients and the wholesale cost per pound.

Fiber Cost/lb Ingredient Sunflower White millet Protein Fat 26 4.1 0.22 0.19 16.9 29 8.3 12 Kibble corn 8.5 3.8 2.7 0.10 15.4 0.40 Oats 6.3 2.4 Cracked corn 3.8 8.5 2.7 0.07 Wheat 12 0.05 1.7 2.3 Safflower 18 17.9 28.8 0.26 Canary grass seed 0.11 11.9 4 10.9