The Widmark equation estimates the blood ethanol concentration, C:
where A is the mass of ethanol ingested in g, W is the body weight in g, and r is the Widmark distribution ratio for ethanol (0.55 mL blood/g body weight for an adult female, 0.68 for an adult male). Other factors needed include the density of ethanol (0.8 g/mL), the concentration of ethanol in the beer (stated as 5% by the problem), the conversion from oz to mL (29.5 mL/oz), and the conversion from lb to g (454 g/lb).
Thus,
and
This result could also be expressed as 0.23 g/dL or 0.23%. The elimination of alcohol from the body occurs at approximately 0.015%/hr, so it is expected that the blood alcohol concentration after 5 hr would be:
