PrepTest 140

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
Appropriate teaching methods AND Significant effort → Broad mastery
Therefore: not Broad mastery → not Appropriate teaching methods

Answer Anticipation:
The argument establishes a conditional and then concludes a version of the contrapositive (missing one of the sufficient conditions), so let's contrapose the premise in order to get it to line up:

not Broad mastery → not Appropriate teaching methods OR not Significant effort

We can see that the conclusion more or less matches up with it minus one of the optional necessary conditions. So in order to get to the conclusion, we need to either rule out not Significant effort, or we need to guarantee not Appropriate teaching methods. The correct answer could either directly rule out the one option ("All students put in significant effort in their studies"), or we can connect those two necessary conditions so that not Appropriate teaching methods is guaranteed (and take the contrapositive):

not Significant effort → not Appropriate teaching methods
Appropriate teaching methods → Significant effort

Answer Explanation:
Appropriate teaching methods → Significant effort. This matches our anticipation. If this answer is true, then the premise guarantees that lacking broad mastery guarantees the studies weren't taught appropriately or didn't put in significant effort, and if they didn't put in significant effort, then they weren't taught appropriately. Therefore, either outcome leads back to not Appropriate teaching methods, thus validating the conclusion.

Key Takeaway:
When an argument establishes a premise with two optional necessary conditions, and it concludes one of them, the correct answer will likely connect the other condition to the first, as we saw here. Additionally, in Strengthen with Sufficient Premise questions, be sure that you're focused on the logical force of the conclusion, as the correct answer will usually meet or exceed that strength in order to be strong enough to justify it.

Incorrect. not Significant effort → not Broad mastery. This answer is a reversal of a portion of the argument. And by stating that something happens "Even if" appropriate methods are used, it's removing appropriate methods as a relevant factor in that relationship, so it's incorrect.

Incorrect. not Appropriate methods → not Broad mastery. This answer is the reversal of the conclusion, so it won't help to justify it.

Incorrect. "[D]oes not always result" is too weak to justify the conclusion of this argument, which is much more definitive than that.

Incorrect. "[D]o not always" is too weak to justify the conclusion of this argument, which is much more definitive than that.