Pharmacy Science and Calculations Sessions 1-6 Practice Test

The total amount of drug in a solution comes from multiplying its concentration by its volume. Here, you have 3 mg of drug per 1 mL, and there are 200 mL. Multiply the two: 3 × 200 = 600. The units mg/mL times mL cancel to give mg, so there are 600 mg of drug in the container. Intuitively, you’re taking 200 milliliters each containing 3 mg, which adds up to 600 mg.