E

argument assumes that there is no other way to know where is the lingo center
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The one who flies is worthy. The one who is worthy flies. The one who doesn't fly isn't worthy

(D)

If the language center is on the left, the stroke must cause some damage. If no damage then CR concludes that the language center is not even on the left side.
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Kick GMAT ass

IMO A. If my answer is correct, I will explain it.

I honestly feel that the answer should be B. The reason I don't like option E is that the argument is not focused on whether it's possible to determine where the language center is exactly located. The argument is a casual: The argument concludes that the damage of the language center causes impairment of linguistic capabilities. This means that the argument assumes that no other cause is possible to this effect of impairment. So, option B points out to this very fact that other causes indeed do not exist.

Conclusion: People who have suffered a serious stroke on the left side of the brain without
suffering any such impairment must have their language centers in the right half.


A. No part of a person’s brain that is damaged by a stroke ever recovers. [Irrelevant]

B. Impairment of linguistic capabilities does not occur in people who have not
suffered any damage to any language center of the brain. [Ok but has nothing to do with the conclusion]

C. Strokes tend to impair linguistic capabilities more severely than does any other
cause of damage to language centers in the brain. [Argument is not about comparison between strokes and others]

D. If there are language centers on the left side of the brain, any serious stroke
affecting that side of the brain damages at least one of them. [Hold on]

E. It is impossible to determine which side of the brain contains a person’s language
centers if the person has not suffered damage to either side of the brain. [Irrelevant]

Answer: D

I will go against the current and chose A.The conclusion says a person must be having language centre in the right half,if he got stroke in the left side w/t suffering any impairements. But wht if the language centre was in left half only & the damaged part recovered? thus there wnt be any impairement? Hence, wnt the argument fall apart? Any takers?

First attempt to post this explanation failed...

The answer is D. The conclusion of the argument is an if-then claim: If a person suffers a serious stroke on the left side AND his/her linguistic capabilities are not impaired, then all his/her language centres are on the right side. The only relevant evidence is the statement that if a language centre is damaged, then a person's linguistic capabilities will be impaired. The contrapositive of the evidence (which is logically exactly the same statement) is that if a person's linguistic capabilities are not impaired, then no language centres were damaged.

We can combine the contrapositive version of the evidence with the "if" part of the conclusion and produce the following: If a person suffers a serious stroke on the left side and his/her linguistic capabilities are not impaired, then no language centres were damaged. This is as far as the evidence gets us. In order to create the entire conclusion of the argument, we need to add one more if-then statement: If no language centres were damaged, then there are no language centres on the left side. This if-then statement is the missing assumption.

Now look at D, and notice that it is the contrapositive of that missing assumption -- which means that it IS the missing assumption, because a contrapositive and its "original" are logically the same statement.
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Grumpy

Kaplan Canada LSAT/GMAT/GRE teacher and tutor

thanks for all ur replies .... the OA is D

this question is ridiculus 'at least one of them'
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The one who flies is worthy. The one who is worthy flies. The one who doesn't fly isn't worthy

IMO D)

If you remove the assumption that stroke does affect a language centre, then arguument fails.