Difficulty: Easy
Correct Answer: All participants in the race are students.
Explanation:
Introduction / Context:This item mixes set restriction (“only students”) with a subset receiving an invitation (all girl participants). We must pick the conclusion guaranteed by the premises and avoid adding unstated coverage to groups not mentioned explicitly.
Given Data / Assumptions:
Concept / Approach:From I), every participant is a student. From II)–III), we know some invitees exist (the girl participants), but nothing is said about non-girl participants. So we can conclude “all participants are students,” but we cannot conclude “all participants are invited.”
Step-by-Step Solution:
Option A: Overreach. Only girl participants are guaranteed invites; other participants may or may not be invited.Option B: Direct consequence of “only students can participate.”Option C: Includes A, which is not guaranteed, so it fails.Option D: Incorrect because B is guaranteed.Option E: While true (some invited are girls), it is not among the original four choices in a standard single-answer format unless we explicitly include it; here, the necessary conclusion requested by the typical pattern is B.Verification / Alternative check:Construct a model where non-girl participants receive no invite; A fails but B remains true. Hence B is the unique necessary conclusion.
Why Other Options Are Wrong:
A assumes all participants invited; not stated.C piggybacks on A.D ignores B’s necessity.Common Pitfalls:Confusing “only students can participate” with “only participants are students.” The former implies participant → student, not the converse.
Final Answer:All participants in the race are students.
Discussion & Comments