The human body is 0.0040% iron. How many milligrams of iron does a 165 pound person contain?

in a body of 165 pounds, the iron content is 2993.707 mg

Explanation:

% iron = 0.0040% = (mass iron / mass human) * 100

⇒ mass iron / mass human = 4 E-5

∴ mass human = 165 pounds

⇒ mass iron = 165 pounds * 4 E-5

⇒ mass iron = 6.6 E-3 pounds * (453.592 g/pound) * (1000 mg/g)

⇒ mass iron = 2993.707 mg iron