A6-ounce serving of a beverage contains 450 ml water, 20 g sugar and 5 g alcohol. how many kcal does this beverage supply? 125

Kcal is the amount of energy a substance can supply to the body. Water has zero calories. Therefore the kcal from this beverage would only be coming from the sugar and alcohol. Assuming that the  sugar is raw and the alcohol is in pure form of ethanol, therefore the amount of kcal per gram of each substance is:

Sugar = 4 kcal / gram

Alcohol = 7 kcal / gram

Therefore the total calories is:

calories = 20 gram * (4 kcal / gram) + 5 gram * (7 kcal / gram)

calories = 80 kcal + 35 kcal

calories = 115 kcal