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- Posts: 8950
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- Fri Jan 21, 2011 12:00 am
#22736
Complete Question Explanation
Parallel Reasoning-SN. The correct answer choice is (A)
The first sentence of this stimulus provides the following conditional diagram:
Max guilty → (not) ask police to investigate
Contrapositive:
Ask police to investigate → Max not guilty
As we can see from the above, the conclusion drawn by the author reflects a valid contrapositive, so the correct answer choice should reflect the same.
Answer choice (A): This is the correct answer choice, as it does indeed reflect a valid contrapositive. The statement and contrapositive can be diagrammed as follows:
Statement: Lucille in next room → I could not see her
Contrapositive: I can see her → Lucille not in next room
Since the conclusion provided by this statement reflects a valid contrapositive, this answer choice perfectly parallels the reasoning in the stimulus.
Answer choice (B): This answer choice provides neither a good parallel nor a valid conclusion. The flawed reasoning can be diagrammed as follows:
Statement: Sam were rich → (not) spend vacation in Alaska
Invalid conclusion: (not) spend vacation in Alaska → Sam rich
The above reasoning reflects a Mistaken Reversal, so this answer choice is incorrect.
Answer choice (C): Here we have another Mistaken Reversal, and another incorrect answer choice, which can be diagrammed as follows:
Statement: Joe over 40 → (not) want to learn to ski
MR Conclusion: (not) want to learn to ski → Joe over 40
Answer choice (D): This choice also reflects an invalid conclusion, so this answer choice is incorrect, but in this case we have a Mistaken Negation:
Statement: Mark good cook → (not) put cinnamon in chili
Mark not good cook → put cinnamon in chili
As we can see from the above diagram, both sides have been negated, but no reversed, so this is a classis Mistaken Negation.
Answer choice (E): This answer choice does reflect valid reasoning, but still fails to parallel the stimulus perfectly. Whereas correct answer choice (A) reflects a valid contrapositive, this answer choice merely reflects a valid restatement:
Statement: Sally sociable → (not) avoid friends
Conclusion: Sally sociable → (not) avoid friends
Because this answer choice does not parallel the stimulus as closely as answer choice (A), answer choice (E) is incorrect.
Parallel Reasoning-SN. The correct answer choice is (A)
The first sentence of this stimulus provides the following conditional diagram:
Max guilty → (not) ask police to investigate
Contrapositive:
Ask police to investigate → Max not guilty
As we can see from the above, the conclusion drawn by the author reflects a valid contrapositive, so the correct answer choice should reflect the same.
Answer choice (A): This is the correct answer choice, as it does indeed reflect a valid contrapositive. The statement and contrapositive can be diagrammed as follows:
Statement: Lucille in next room → I could not see her
Contrapositive: I can see her → Lucille not in next room
Since the conclusion provided by this statement reflects a valid contrapositive, this answer choice perfectly parallels the reasoning in the stimulus.
Answer choice (B): This answer choice provides neither a good parallel nor a valid conclusion. The flawed reasoning can be diagrammed as follows:
Statement: Sam were rich → (not) spend vacation in Alaska
Invalid conclusion: (not) spend vacation in Alaska → Sam rich
The above reasoning reflects a Mistaken Reversal, so this answer choice is incorrect.
Answer choice (C): Here we have another Mistaken Reversal, and another incorrect answer choice, which can be diagrammed as follows:
Statement: Joe over 40 → (not) want to learn to ski
MR Conclusion: (not) want to learn to ski → Joe over 40
Answer choice (D): This choice also reflects an invalid conclusion, so this answer choice is incorrect, but in this case we have a Mistaken Negation:
Statement: Mark good cook → (not) put cinnamon in chili
Mark not good cook → put cinnamon in chili
As we can see from the above diagram, both sides have been negated, but no reversed, so this is a classis Mistaken Negation.
Answer choice (E): This answer choice does reflect valid reasoning, but still fails to parallel the stimulus perfectly. Whereas correct answer choice (A) reflects a valid contrapositive, this answer choice merely reflects a valid restatement:
Statement: Sally sociable → (not) avoid friends
Conclusion: Sally sociable → (not) avoid friends
Because this answer choice does not parallel the stimulus as closely as answer choice (A), answer choice (E) is incorrect.
