80 cal/ g is same as 80 calories in each 1 gram. so,
80 cal= 1 gram
first, we need to convert the kg into grams. all you have to do is multiply by 1000 or move the decimal three times to the right.
0.05 kg= 50.0 grams
50.0 g (80 cal/ 1 gram)= 4000 calories