# If the proper dosage of a drug is 2 mg/kg of body weight, how many milligrams would a 110-lb individual need?

Mar 4, 2015

Your patient needs $\text{100 mg}$.

SInce your drug's dose is expressed in mg per kg, you'll need to convert it to mg per pound first, and then determine how much a 110-lbs patient would need.

$2 \text{mg"/"kg" * "1 kg"/"2.20462 lbs" = "0.9072 mg/lbs}$

then

$\text{110 lbs" * 0.9072"mg"/"lbs" = "99.8 mg}$

Rounded to one sig fig, the number of sig figs in 2 mg, the answer will be

m_("drug") = "100 mg"

You can do this in one longer step as well

$2 \text{mg"/"kg" * "1 kg"/"2.20462 lbs" * "110 lbs" = "100 mg}$