1. **State the problem:** We need to find out how many boxes of Humalog Cartridges a patient requires for a 6-month supply. 2. **Given information:** - Insulin concentration: 100 units/mL - Dosage: 20 units three times a day (tid) - Duration: 6 months 3. **Calculate total daily units:** $$20 \text{ units} \times 3 = 60 \text{ units/day}$$ 4. **Calculate total units for 6 months:** Assuming 1 month = 30 days, $$6 \text{ months} \times 30 \text{ days/month} = 180 \text{ days}$$ Total units needed: $$60 \text{ units/day} \times 180 \text{ days} = 10800 \text{ units}$$ 5. **Determine volume of insulin needed:** Since concentration is 100 units/mL, $$\text{Volume} = \frac{10800 \text{ units}}{100 \text{ units/mL}} = 108 \text{ mL}$$ 6. **Calculate number of boxes:** Assuming each box contains cartridges with a total volume of 3 mL (typical for Humalog cartridges), $$\text{Number of boxes} = \frac{108 \text{ mL}}{3 \text{ mL/box}} = 36 \text{ boxes}$$ **Final answer:** The patient requires **36 boxes** of Humalog Cartridges for the 6-month supply to ensure they do not run out before returning to Canada.