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GATE 2021 CS – Question 9

General Aptitude · Analytical Aptitude: Logical Reasoning and Deduction · 2 marks · Multiple choice

Given below are two statements 1 and 2, and two conclusions I and II.
Statement 1: All bacteria are microorganisms.
Statement 2: All pathogens are microorganisms.
Conclusion I: Some pathogens are bacteria.
Conclusion II: All pathogens are not bacteria.
Based on the above statements and conclusions, which one of the following options is logically CORRECT?

  1. Only conclusion I is correct
  2. Only conclusion II is correct
  3. Either conclusion I or II is correct.
  4. Neither conclusion I nor II is correct.

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Show answer and explanation

Correct answer: (C) Either conclusion I or II is correct.

Explanation

Both statements share the middle term 'microorganisms' in the predicate, so nothing definite follows about pathogens and bacteria. I and II are complementary (subaltern/contradictory pair), so either holds. The official key accepts both C and D.