Logical deduction – age order and transitivity Given: Joe is younger than Kathy. Mark was born after Joe (so Mark is younger than Joe). Question: If those two facts are true, is the statement “Kathy is older than Mark” true, false, or uncertain?
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ATrue
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BFalse
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CUncertain
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DBoth true and false
Answer
Correct Answer: True
Explanation
Introduction / Context:This verbal reasoning item tests your ability to use transitive ordering on ages. If person A is younger than person B, and person C is younger than person A, where does that place C relative to B? You must translate the English statements into a consistent sequence.
Given Data / Assumptions:
- Joe is younger than Kathy.
- Mark was born after Joe (so Mark is younger than Joe).
- Claim to evaluate: “Kathy is older than Mark.”
- Ages are strictly comparable, and “born after” means “younger.”
Concept / Approach:Treat “younger than” as a strict order. Use transitivity: if Mark is younger than Joe and Joe is younger than Kathy, then Mark is younger than Kathy. Therefore Kathy is older than Mark.
Step-by-Step Solution:1) Translate: Joe younger than Kathy ⇒ Joe < Kathy.2) Translate: Mark born after Joe ⇒ Mark younger than Joe ⇒ Mark < Joe.3) Chain them: Mark < Joe and Joe < Kathy ⇒ Mark < Kathy.4) Convert back: If Mark is younger than Kathy, then “Kathy is older than Mark” is True.
Verification / Alternative check:Pick sample ages: Kathy 15, Joe 13, Mark 12. All statements fit, and the conclusion is clearly true.
Why Other Options Are Wrong:
- False: Contradicts the transitive order.
- Uncertain: There is no ambiguity; the order is forced by the two premises.
- Both true and false: Logical truth values are not both simultaneously applicable here.
Common Pitfalls:Confusing “born after” (younger) with “older than,” or overlooking transitivity can lead to uncertainty where none exists.
Final Answer:True