GMATNinja generis VeritasKarishma nightblade354Please validate my argument understanding and PoE
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For the argument to be logically correct, it must make which one of the following assumptions?
Which one of answer choices must be true for the conclusion to be valid?
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Train service suffers when a railroad combines commuter and freight service. By dividing its attention between its freight and commuter customers, a railroad serves neither particularly well. Therefore, if a railroad is going to be a successful business, then it must concentrate exclusively on one of these two markets.
Conclusion: Train service must concentrate exclusively on one of two markets: Market A: commuter service
Market B: freight service
Necessary condition: usually the conclusion: Train service must concentrate exclusively on one of these two markets.
Sufficient condition: a railroad is going to be a successful business
Why:
Premise: If train service divides its attention on both, it does well in neither of them.
Approach: For an assumption, try to attack the conclusion ie necessary condition.
If a suff condition exists without necessary condition, my conclusion breaks apart
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(A) Commuter and freight service have little in common with each other.
Whether commuter and freight services have more aspects in common or fewer aspects in common,
(A) does not help to invalid my claim. Out of scope -1
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(B) The first priority of a railroad is to be a successful business.
Priority?? Another huge leap? Out of scope -2
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(C) Unless a railroad serves its customers well, it will not be a successful business.
Negate this:
Even if a railroad serves its customers well, it will not be a successful business
Now my necessary condition is under danger since even if railroad is serving its customers well,
as per this choice: it will not be a successful business.
Hence, the conclusion is invalid
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D) If a railroad concentrates on commuter service, it will be a successful business.
Nope, arguments says to concentrate on ANY ONE, see highlighted text.
Railroad can concentrate on EITHER commuter or freight services and become a successful business.
Since the conclusion is not broken on negation, this option is rejected.
Negated version:
If a railroad concentrates on commuter service, it will NOT be a successful business.
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(E) Railroad commuters rarely want freight service as well.
What commuters want is totally out of scope.