Marks pet needs to eat at least 18 grams of fiber but less than 25 grams of protein each day. Mark gives his dog Food A and Food B throughout the day. Food A has 2 grams of fiber and 3 grams of protein in each serving. Food B has 4 grams of fiber and 1 gram of protein for each serving.
a. Write a system of inequalities that determine the maximum and minimum amount of each food Mark can give his pet each day. Will the amount of Food A or B ever be negative? Please account for this in your system of inequalities.
b. Give three solutions that would solve Marks pet needs. Show that each solution works.