The calorie count of a serving of food can be computed based on its composition of carbohydrate, fat, and protein. The calorie count C for a serving of food can be computed using the formula C=4h+9f+4p , where h is the number of grams of carbohydrate contained in the serving, f is the number of grams of fat contained in the serving, and p is the number of grams of protein contained in the serving.
A serving of raisins contains 115 calories and 21 grams of carbohydrate. If raisins are a fat-free food, how much protein is provided by this serving of raisins?
