Difficulty: Easy
Correct Answer: Both I and II follow.
Explanation:
Introduction / Context:
This is a classic use of a universal affirmation combined with a universal exclusion to deduce two symmetric “no overlap” conclusions.
Given Data / Assumptions:
Concept / Approach:
If set X is a subset of Y and a third set Z has empty intersection with Y, then Z must also be disjoint from X. Also, “No Eskimos are English-speaking” is logically equivalent to “No English-speakers are Eskimos.”
Step-by-Step Solution:
1) Because Americans ⊆ English-speakers and Eskimos share no members with English-speakers, Eskimos cannot be Americans. Conclusion I is true.2) The premise “No Eskimos are English-speaking” is symmetric: it also entails “No English-speakers are Eskimos.” Conclusion II is true.
Verification / Alternative check:
Suppose English-speakers = {e1, e2}, Americans = {e1}, Eskimos = {k1}. Then Americans ⊆ English-speakers and Eskimos disjoint from English-speakers; both conclusions hold.
Why Other Options Are Wrong:
Any option denying one of the conclusions contradicts the direct consequences of the premises.
Common Pitfalls:
Overlooking the symmetry of “No A are B.” The statement implies two identical non-overlap claims by swapping A and B.
Final Answer:
Both I and II follow.
Discussion & Comments