csateasy

Examine the following statements:

  1. 1.All trains are run by diesel engine.
  2. 2.Some trains are run by diesel engine.
  3. 3.No train is run by diesel engine.
  4. 4.Some trains are not run by diesel engine.
  1. A.1 and 2
  2. B.2 and 3
  3. C.1 and 3
  4. D.1 and 4
▶ Answer & Explanation

Correct answer: C. 1 and 3

In syllogistic logic, a valid conclusion can often be drawn from premises that are contradictory. Statements 1 and 3 are direct contradictions: if all trains are run by diesel, then it's impossible for no train to be run by diesel, and vice-versa. One must be true and the other false, which is a foundational concept in logical reasoning.

Source: UPSC csat 2011

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