Difficulty: Easy
Correct Answer: Conclusions I and II follow
Explanation:
Introduction / Context:
This problem combines particular and universal premises across five terms. We must check two candidate conclusions.
Given Data / Assumptions:
Concept / Approach:
Use subset chaining for universals and existence from particulars. If Numbers ⊆ Letters ⊆ Words, then every Number is a Word.
Step-by-Step Solution:
1) Because all Numbers are Words, if any Numbers exist, then some Words are Numbers.2) Existence of Numbers is guaranteed by “some locks are numbers.” Hence Conclusion I is necessary.3) Those Locks that are Numbers are also Letters (Numbers ⊆ Letters). Therefore “Some locks are letters” is necessary (Conclusion II).
Verification / Alternative check:
Mark an element that is both Lock and Number; propagate along the universal chain to confirm it is a Letter and therefore a Word.
Why Other Options Are Wrong:
Any option omitting I or II ignores either the existential support or the universal chain.
Common Pitfalls:
Failing to leverage the guaranteed existence from a “some” premise before applying universal inclusions.
Final Answer:
Conclusions I and II follow.
Discussion & Comments