Consider a Food That Yields 300 Kcal Per Serving of Which

Consider a food that yields 300 kcal per serving of which 100 kcal are from fat. Which of the following could be used to calculate the percent from fat?

A) 9 $\times$ 300 $\times$ 100
B) (100 / 300) $\times$ 100
C) (300 / 100) $\times$ 100
D) [(300 - 100) / 300] $\times$ 100