GMAT 逻辑分析题 (18)

sdcar2010

When a model is exercising the legs, it is important to exercise both legs equally in order to maintain a perfect posture. After all, balanced leg development is needed to maintain a perfect posture, since both legs must appear to be in balanced development when striking a pose on the runway in order to capture the heart of the audience.

Which one of the following is an assumption required by the argument?

(A) Legs that are equally developed will be enough for a model to capture the heart of the audience.
(B) Exercising legs unequally tends to lead to unbalanced leg development.
(C) Provided that a model exercises both legs equally, the model will be able to maintain a perfect posture.
(D) If a model exercises both legs unequally, the model’s posture will be irreparably damaged.
(E) If a model has unbalanced leg development, the model tends to exercise both legs unequally.

woaihenglia

我选B，请问正确答案是？

kevin0214

选B，其实跟人大通过法案那题很像

sdcar2010

Right on!  B is the correct choice.

woaihenglia

楼主顺便说下，你对这类形题的解题思路吧，最好写英文哦，呵呵。谢谢

sdcar2010

When a model is exercising the legs, it is important to exercise both legs equally in order to maintain a perfect posture. After all, balanced leg development is needed to maintain a perfect posture, since both legs must appear to be in balanced development when striking a pose on the runway in order to capture the heart of the audience.

Conclusion: To maintain a perfect posture, a model needs to exercise both legs equally
Formal logic: maintain posture --> exercise legs equally

Premise: To maintain a perfect posture, a model needs balanced leg development
Formal logic: maintain posture --> balanced leg development

How could you complete the logic chain "maintain posture" --> ?? --> "exercise leg equally" in the conclusion based on the premise of "maintain posture --> balanced leg development"?  Just replace "??" with "balanced leg development"! Therefore, for the conclusion to hold, the assumption is "balanced leg development --> exercise legs equally" which was stated in its contrapositive form in answer B.

All assumption questions hinge on finding the gap between the premise and the conclusion.

livebelieve

逆反命题