For a two-phase dosing scenario where 21 days are at 1 tablet daily and the remainder is at 2 tablets daily, the total days supply for a 106-tablet prescription is closest to which value?

• A. 60 days
• B. 63.5 days
• C. 70 days
• D. 75 days

Answer: (B)

Two-phase dosing means you allocate part of the tablets to a lower daily dose and the rest to a higher daily dose, then sum the days from both phases to get the total days’ supply. Start with the first phase: 21 days at 1 tablet per day uses 21 tablets. Subtract that from the total tablets: 106 − 21 = 85 tablets remain. In the second phase, you take 2 tablets daily, so those 85 tablets last 85 ÷ 2 = 42.5 days. Add the two phases together: 21 days + 42.5 days = 63.5 days. So the total days’ supply is 63.5 days.