1. **State the problem:** We have a 2.5% intravenous drug solution infused at a rate of 1.5 ml/min. We want to find the amount of drug in milligrams (mg) infused in one hour. 2. **Understand the concentration:** A 2.5% solution means 2.5 grams of drug per 100 ml of solution. 3. **Convert concentration to mg/ml:** Since 1 gram = 1000 mg, 2.5 grams = 2500 mg. Therefore, concentration = $\frac{2500\text{ mg}}{100\text{ ml}} = 25\text{ mg/ml}$. 4. **Calculate total volume infused in one hour:** Rate = 1.5 ml/min Time = 60 minutes Total volume = $1.5 \times 60 = 90$ ml 5. **Calculate amount of drug infused:** Amount = concentration $\times$ volume Amount = $25 \text{ mg/ml} \times 90 \text{ ml} = 2250$ mg **Final answer:** The amount of drug infused in one hour is **2250 mg**.