Let's take a look at this question from a strategic point of view that highlights common patterns on the GMAT. Our first strategic item of business is to identify leverage in the question stem to identify the problem type. This question isn't subtle; after all, the question asks for an "
assumption on which the argument depends." "
Required Assumption" questions are a sub-type of traditional Strengthen questions, but for those of you studying for the GMAT, it might be worth noting that Required Assumption questions play by
slightly different rules.
If a question asks you for an unstated fact (in other words, an "
assumption") upon which an argument "
depends", that is a pretty high bar. With regular Strengthen questions, any answer choice that helps the conclusion to be valid can strengthen the argument. However, when a problem asks for an assumption on which the argument "
depends" or "
relies", you are looking for an answer choice that is FUNDAMENTALLY CRITICAL to the viability of the conclusion.
In this argument, the conclusion is "
clearly only children take this festival seriously." The word "
clearly" is our trigger word that identifies this as a conclusion. Notice that conclusion contains the word "
only" -- an extreme scope limiter that has a very high bar of proof.
Now that we have identified the conclusion, the gap in the logic should be fairly obvious: even though the "
only" attendees in ninja costumes are children doesn't necessarily mean that "
only" the children take the festival seriously. In my classes, I call this type of error "
Correlation is not Causation." Just because just the children dress up doesn't mean that their costumes -- and and their costumes alone -- prove that they are the "only" serious fans. (Think about it: you don't have to dress as Darth Vader to prove you are a serious Star Wars fan any more than you have to carry around a block of cheddar to prove you like cheese!) Could there be other ways that a "serious" fan might show his/her colors? Who says that dressing up is the only way? What if their parents are the super-fans who subject their kids to embarrassing costumes? The kids themselves could still hate ninjas! Wearing a costume isn't necessarily the only proof that you love ninjas!
The argument requires a statement that shows that dressing up as a ninja is the "only" way to demonstrate that a fan is "serious." The correct answer choice will do this. Anything else is a trap.
Answer choice
A is a beautiful trap answer. It states, "
Any attendee who dresses up as a ninja takes the festival seriously." At first glance, this sounds really good. After all, this proves that the kids who dress up are serious fans. But this answer DOESN'T prove that the kids are the "only" serious fans. This strengthens the argument, since, after all, it shows that the kids aren't just being dressed up by their parents. But it fails to show that dressing up is the "only" sign of a serious fan. What if there are other ways that a fan can be identified? This answer falls short of being an assumption upon with the argument "depends."
Answer choice
B is the right answer, but it is deliberately worded in an obnoxious way. (I call this deceptive technique "
Convoluted Camouflage" in my classes.) Notice how
B uses a double negative to intentionally hide what is really happening. ("
No attendee who takes the festival seriously would fail to dress up as a ninja" could also be translated "
All attendees who take the festival seriously would dress up as a ninja.") This fits the criteria we are looking for. Since this shows that dressing up as a ninjas is the "only" way to demonstrate that a fan is serious, we have our answer.
Answer choice
C also uses a double negative to intentionally hide what is really happening. But in this case, answer choice
C is overkill. The argument doesn't "depend" on the fact that only ninja-costumed fans attend the festival. Answer choice
C also doesn't focus on the logical gap. It says nothing about whether dressing up is the "only" way to demonstrate that a fan is "serious." Get rid of it.
Likewise, answer choice
D does nothing to address the logical gap. Whether a dress code exists might be interesting background information, but -- dress code or no dress code --
D is not a fact
required by the argument. Get rid of this as well.
Answer choice
E uses a subtle shift of wordplay to trap novice test takers. The original argument is trying to connect wearing ninjas costumes with being a "
serious" attendee. However, being a "
serious" attendee is not the same thing as being "
taken seriously" by other attendees. The similar verbiage is a distracting trap, but in the end it still doesn't focus on the logical gap.
E is also gone.
So, we have our answer.
Only B truly answers the question, giving us a statement upon which the argument "
depends."
Now, for those of you studying for the GMAT, here is a review of some of the major takeaways with this question: First, notice the difference in approach between
Strengthen questions and
Required Assumption questions. Of course, these two question types are related. Both question types require you to recognize the logical gap between the conclusion and the rest of the argument. But Required Assumption questions have a higher standard. One answer (
A) could arguably strengthen the argument, but that is not sufficient. 3 of the 5 answer choices (
C,
D, and
E) fail to focus on the logical gap presented in the question stem. In the end, there is only one answer upon which the argument "
depends": answer choice "
B". It's true meaning is hidden by some "
Convoluted Camouflage", but that is a normal pattern of the GMAT. This problem is a great reminder for making sure you know exactly what the question is asking and not getting distracted by other things.