Answer
1 gram of carbohydrate produces 4 kilocalories.
1 gram of protein produces 4 kilocalories.
1 gram of fat produces 9 kilocalories.
The given 100 gram of food will produce 290 kilocalories.
Work Step by Step
Total amount of food = 100g
Protein in food = 20% of 100 = $\frac{20}{100}\times100$ = 20g
Energy by protein = 20*4 = 80 kilocalories
Carbohydrates in food = 30% of 100 = $\frac{30}{100}\times100$ = 30g
Energy by carbohydrates = 30*4 = 120 kilocalories
Fat in food = 10% of 100 = $\frac{10}{100}\times100$ = 10g
Energy by fat = 10*9 = 90 kilocalories
Total energy = 80+120+90 = 290 kilocalories.
