Given below are two statements (arguments): - All professors are researchers. - Some scientists are professors. Which of the given conclusions is logically valid and is inferred from the above arguments? A. All scientists are researchers B. All professors are scientists C. Some researchers are scientists D. No conclusion follows

GATE 2013 · General Aptitude · Statements Follow · medium

Answer: Option C — Some researchers are scientists — is the only logically valid conclusion.

1. Derive the valid conclusion via existential carry-over: Premise 2: Some scientists are professors => There exist individuals who are in (Scientists AND Professors). Premise 1: All professors are researchers => Those same individuals, being professors, are also in Researchers. Therefore: Some scientists are researchers (equivalently, some researchers are scientists). Option C is correct.
2. Eliminate incorrect options: Option A (All scientists are researchers): We only know SOME scientists are professors; other scientists may not be professors and thus not necessarily researchers. Incorrect. Option B (All professors are scientists): This is the converse of Premise 2's implication direction. A scientist being a professor does not mean all professors are scientists. Incorrect. Option D (No conclusion follows): We just derived Option C, so this is incorrect.