If a patient is prescribed a total of 40 mg of medication daily and given 420 mg, how many days will the supply last?

To determine how many days a supply of 420 mg will last when the patient is prescribed 40 mg daily, you can divide the total supply by the daily dose.

In this case, the calculation is as follows:

1. Start with the total amount of medication: 420 mg.

2. Divide that by the daily dose: 420 mg ÷ 40 mg/day = 10.5 days.

This results in 10.5 days, which means the supply will last for 10 full days, with some medication remaining for part of the 11th day. However, if the question asks for the maximum number of complete days the supply will last, we typically round down to the nearest whole number.

The best answer in this context is the one that accurately reflects how long the full prescription will last in whole days, which indeed is 10 days, not 7.

Therefore, the correct reasoning is that the daily requirement of 40 mg means that over a total supply of 420 mg, the patient would have full daily doses available for 10 complete days, according to the calculations. The answer should indicate this understanding rather than representing an incomplete assessment of the supply based on the dosage.

Correct reasoning should focus on