Q. Two Statements are given followed by two Conclusions:
Statements: All cats are dogs. All cats are black.
Conclusion-l: All dogs are black.
Conclusion-ll: Some dogs are not black.
Which of the above Conclusions logically follows/follow from the two given Statements disregarding commonly known facts?
(a) Only Conclusion-l
(b) Only Conclusion-II
(c) Neither Conclusion-I nor Conclusion-II
(d) Both Conclusions-I and Conclusion-Il
Correct Answer: (c) Neither Conclusion-I nor Conclusion-II
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
All cats are dogs. All cats are black.
1. For Conclusion I – “All dogs are black”:
– While we know all cats are black and all cats are dogs
– We cannot conclude all dogs are black
– Because not all dogs may be cats
– Example: There could be dogs that are not cats, and these dogs could be any color
2. For Conclusion II – “Some dogs are not black”:
– We cannot conclude this either
– The statements give no information about dogs that are not cats
– Making any assumption about non-cat dogs would be illogical
Therefore:
Neither conclusion can be logically derived from the given statements. The statements only tell us about cats (that they are dogs and they are black) but give no complete information about dogs.
Correct Answer: Neither Conclusion-I nor Conclusion-II follows from the given statements.