Difficulty: Medium
Correct Answer: Only I and IV follow
Explanation:
Introduction / Context:Two nested universals are provided. We assess which of the four conclusions are compelled by these inclusions.
Given Data / Assumptions:
Concept / Approach:Transitivity of subset gives Dogs ⊆ Pictures (I). The converses (II, III) are not supported. From Books ⊆ Pictures and non-emptiness, there exists at least one entity that is both picture and book, validating IV.
Step-by-Step Solution:
I) Dogs ⊆ Books and Books ⊆ Pictures imply Dogs ⊆ Pictures — true.II) 'All books are dogs': converse, not implied.III) 'All pictures are dogs': overly strong; not implied.IV) 'Some pictures are books': if any book exists, that book is a picture — validates an existential.Verification / Alternative check:Take one concrete book; it is also a picture, satisfying IV. Dogs being a subset of books ensures I.
Why Other Options Are Wrong:Options that include II or III assume unsupported converses or overgeneralization.
Common Pitfalls:Confusing subset direction and presuming equivalences where only one-way inclusion exists.
Final Answer:Only I and IV follow.
Discussion & Comments