PrepTest 142

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Grapefruit juice makes medicine act like more medicine. Getting too much medicine is dangerous; you should take the lowest possible dose. So the best practice is to take lower doses with grapefruit juice.

Answer Anticipation:
This entire argument is about the dose of medicine that people are taking. Too much is bad, and taking just the right amount is "always desirable." The argument then tries to figure out a way to lower doses by mixing medication with grapefruit juice, since a chemical in the juice has medication-enhancing effects.

There's a lot of science/medicine in this, so we're probably on safer ground identifying what we should be looking for generally rather than trying to get specific. The argument, again, is all about doses, so any answer that states the grapefruit juice/medicine cocktail might have a different dose, or act like a different dose, than expected would weaken this conclusion.

Answer Explanation:
If it's hard to get the "right dose" of the grapefruit chemicals to enhance the dose of the medication to the right level, and getting the wrong dose is dangerous, then this answer makes it seem as if taking medication with grapefruit juice could lead to overdosing (or underdosing). Both would be bad, so this weakens the argument.

Key Takeaway:
When the content is outside your area of comfort, sometimes it's better to come up with a clear idea of what the answer is going to do rather than have a specific idea of what the answer is going to say. Getting too specific risks anticipating an answer that doesn't show up, anyway, so staying more general can be more likely to yield results!

Incorrect. The argument doesn't bring cost in as a factor—it just focuses on dosage.

Incorrect. This answer strengthens an argument that the grapefruit juice chemicals by themselves have the drug-enhancing effect, but it doesn't affect an argument about whether it's a good idea to take them with medication to enhance effects.

Incorrect. How it works doesn't weaken an argument about whether it should be used.

Incorrect. This answer is trying to make you think it weakens the argument by having doctors recommend against mixing grapefruit juice and medication. However, things have changed since then—we now know how grapefruit juice has the effect—and so their advice might be outdated, as well. As such, this doesn't weaken the conclusion.