For a medication with a half-life of 3 hours, how much of a 200 mg dose remains after 6 hours?

To determine how much of the drug remains after a certain period, you can use the concept of half-life, which is the time it takes for half of a substance to be eliminated or to decay. In this case, the medication has a half-life of 3 hours.

After the first half-life (3 hours), half of the 200 mg dose will remain. This means:

200 mg / 2 = 100 mg

After another 3 hours (which totals 6 hours), you apply the half-life again to the remaining amount:

100 mg / 2 = 50 mg

Since the question asks for the amount remaining after 6 hours, we see that indeed 50 mg remains. This reasoning aligns perfectly with the concept of half-lives and how they reduce the quantity of a substance over time. Thus, the correct answer is clearly 50 mg.