An English unit used in pharmaceutical work is the grain (gr). There are 15 grains in 1 gram. An aspirin tablet contains 5.0 gr of aspirin. A 145 lb person takes two aspirin tablets. Calculate the dosage of aspirin, which is the number of milligrams of aspirin per kilogram of body weight. (1 lb = 453.5 g)

10.2 mg/kg

Explanation:

An aspirin tablet contains 5.0 gr of aspirin. Two aspirin tablets contain 2 * 5.0 gr = 10 gr. The mass of aspirin, in grams, is:

10 gr * (1 g/15 gr) = 0.67 g = 670 mg

The person has a body weight of 145 lb. The mass of the person, in kilograms, is:

145 lb * (0.4535 kg/1 lb) = 65.8 kg

The dosage of aspirin is:

670 mg/65.8 kg = 10.2 mg/kg