Question

The average 70 kg (150 lb) being has 5.5 L of blood (1.05 g/mL). How many 1 oz drinks of 20% alcohol by volume (40 proof) must be consumed for the blood alcohol content (BAC) to exceed 0.1 (BAC is g alcohol per 100 mL blood)? Assume that all of the alcohol consumed goes directly into the blood.

Answer 1

The total blood given is 5.5 liters

Thus, total alcohol needed for BAC (blood alcohol content) to exceed 0.1 gram per 100 ml will be 0.1/100 × 5500 = 5.5 grams alcohol.

1 oz = 28.3 grams

28.3 gram water = 28.3 ml

It has 20 percent alcohol by volume,

Therefore, alcohol in one drink will be:

20/100 × 28.3

= 5.66 ml

= 5.66 × 0.79 (density of ethanol)

= 4.47 gram

Thus, no of drinks will be 5.5 g / 4.47 g = 1.2

Hence, 1.2 drinks will make the BAC to exceed 0.1 g / 100 ml in the blood.