求解一道GWD逻辑，多谢高手指点！！

iamdurant · 发表于 2011-6-19 22:34:02

GWD7-Q27:

A significant number of complex repair jobs carried out by Ace Repairs have to be reworked under the company’s warranty.The reworked jobs are invariably satisfactory.When initial repairs are inadequate, therefore, it is not because the mechanics lack competence; rather, there is clearly a level of focused concentration that complex repairs require that is elicited more reliably by rework jobs than by first-time jobs.

The argument above assumes which of the following?

A.There is no systematic difference in membership between the group of mechanics who do first-time jobs and the group of those who do rework jobs.

B.There is no company that successfully competes with Ace Repairs for complex repair jobs.

C.Ace Repairs’ warranty is good on first-time jobs but does not cover rework jobs.

D.Ace Repairs does not in any way penalize mechanics who have worked on complex repair jobs that later had to be reworked.

E.There is no category of repair jobs in which Ace Repairs invariably carries out first-time jobs satisfactorily.
答案是A,解释说是假设题就是取非消弱，不理解。。。。求高手指教，谢谢

sdcar2010 · 发表于 2011-6-19 22:45:42

Necessary assumption. Use negation.

Part of the main conclusion says: When initial repairs are inadequate, therefore, it is not because the mechanics lack competence.

If you negate A), you have:
There is SOME systematic difference in membership between the group of mechanics who do first-time jobs and the group of those who do rework jobs.
If this is true, there is a difference in skills between the two groups of mechanics and the first group might be less competent than the second and the reason why the first repair fails is due to incompetence. Thus, the conclusion of the argument falls apart.

求解一道GWD逻辑，多谢高手指点！！

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