Aserving of food contains 15 g carbohydrate, 3 g protein, 5 g fat, 5 mg vitamin c, and 100 ml water. based on this information, a serving of this food supplies kcal

117kcal. To know the total kcal, we first have to determine the conversion rate for carbohydrates, fat, protein, water, and grams of vitamins.

Here are the conversion rates:

4kcal per gram of protein.
4kcal per gram of carbohydrate.
9kcal per gram of fat. 
0kcal per gram of vitamin.
0kcal per milliliter of water

From the given values, we can say that the food serving gives 117kcal.