Logical reasoning PrepTest 140 · Section 2 · Question 3

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Humorous → Attract and Hold attention long enough to convey message
Effective ad → Convey its message
Therefore Ð Effective ad → Humorous

Answer Anticipation:
This argument has a lot of conditional language ("the only", "if", "must"), so there's likely a conditional logic flaw.

The conclusion here establishes that all effective ads are humorous—in other words, being humorous is necessary for an ad to be effective. However, the premise establishes being humorous as a sufficient condition to convey a message (itself a necessary condition for being effective). That's an illegal reversal.

While the correct answer might state simply that the argument confuses a sufficient condition for a necessary one, we should be sure we know which statement is being reversed. And as we discussed, since the first conditional premise flips the conclusion and the second doesn't, it's that first statement—it's treating humorousness as a necessary condition for conveying a message instead of a sufficient condition.

Answer Explanation:
This answer, rephrased, states that the argument assumes ("takes for granted") humor is necessary ("nothing but humor") to convey a message, thus reflecting the illegal reversal of that conditional statement.

Key Takeaway:
There being conditional logic in an Errors in Reasoning question almost always means there's a conditional logic flaw. Identifying not only the flaw but which individual statement is reversed or negated will lead you directly to the correct answer.

Incorrect. The argument establishes that humor accomplishes both of these, so it doesn't confuse one for the other.

Incorrect. This answer highlights a potential illegal reversal, but not the one present in the stimulus. The conditional statement discussing effectiveness aligns with the conclusion (they both have the same sufficient condition), so it's not illegally reversed.

Incorrect. The conclusion seems to use "effective" in the same sense as the premise—conveying a message to influence consumers.

Incorrect. It doesn't assume that that's the only purpose. It establishes that conveying a message is a requirement for an effective ad.