Some of the explanations here are ridiculously complicated.
The argument states: "Clearly only children take this festival seriously, for they are the only attendees who bother to dress up as ninjas."
This
actively assumes that dressing up as a Ninja is a requirement/ indicator for those who take this festival seriously.
Passively, we can make many assumptions required for this argument to hold, but here are a few:
- People who do not dress up as a ninja do not take the festival seriously (most inadvertent)
- People who don't walk around the festival holding a samurai sword are serious attendees
(A) and (B) Match these pre-thought assumptions closest.
More complicated reasoning why (A) is incorrect and (B) is right:
The argument uses conditional reasoning. "If A occurs then B will definitely occur" thus if B occurs it is sufficient to say A has occured.
Only Children take the festival seriously, for they are the only attendees who bother to dress up as ninjas
It is sufficient to say someone takes the festival seriously if they dress up as a ninja (necessary condition)
Here's a simpler example from powerscore:
Logical relationship of sufficient and necessary conditions.
If someone gets an A+ on the test, then they must have studied for the test.
Thus, getting an A+ on the test is sufficient to say that someone must have studied
(A) states: Any attendee who dresses up as a ninja takes the festival seriously. This reverses the necessary and sufficient conditions whereas (B) reinforces the Sufficient-necessary relationship above by denying the possibility of any other state. (B) No attendee who takes the festival seriously (sufficient) would fail to dress up as a ninja (necessary)
Less complicated reasoning why (A) is incorrect and (B) is right:Try negating each answer:
(A)
Not Any attendee who dresses up as a ninja takes the festival seriously.
So some who dress up as a ninja take the event seriously, some don't. The ambiguity of the number of attendees who could potentially take the events seriously but who fail to dress up as a ninja isn't clear.
(B)
Someattendee(s) who take the festival seriously would
not fail to dress up as a ninja.
Therefore its clear that if people were serious they would dress up as ninjas.