UPSC CSE Prelims 2022
Statement-1: All pens are books.
Statement-2: No chair is a pen.
Conclusion-I: All chairs are books.
Conclusion-II: Some chars are pens.
Conclusion-III: All books are chairs.
Conclusion-IV: No chair is a book.
Which one of the following is correct?
The correct option is (D) None of the conclusions follows. This is determined by evaluating each conclusion against the given statements using principles of logical deduction, considering all possible valid interpretations of the relationships between the categories.
To assess the conclusions, we interpret the statements:
Based on these statements, we analyze each conclusion:
Conclusion-I: All chairs are books.
This conclusion does not logically follow. While chairs are distinct from pens, and pens are a subset of books, the relationship between chairs and books is not definitively established. Chairs could be entirely outside the set of books, or they could partially or entirely overlap with the set of books, provided they do not overlap with pens. Since there are valid scenarios where not all chairs are books, this conclusion is not logically derivable.
Conclusion-II: Some chairs are pens.
This conclusion directly contradicts Statement-2, which explicitly states, "No chair is a pen." Therefore, this conclusion is false.
Conclusion-III: All books are chairs.
This conclusion does not logically follow. If all books were chairs, then by Statement-1, all pens (which are books) would also necessarily be chairs. However, Statement-2 asserts that "No chair is a pen," meaning no pen can be a chair. This creates a contradiction. Hence, this conclusion is false.
Conclusion-IV: No chair is a book.
This conclusion does not logically follow. Similar to Conclusion-I, the relationship between chairs and books is not definitively established. Chairs could be entirely outside the set of books, or they could partially or entirely overlap with the set of books (excluding the pens within books). Since there are valid scenarios where some chairs are books, this conclusion is not logically derivable.