Roland: The alarming fact is that 90 percent of the people in the country now report that they know someone who is unemployed.

Sharon: But a normal, moderate level of unemployment is 5 percent, with one out of 20 workers unemployed. So at any given time if a person knows approx. 50 workers, one or more will very likely be unemployed.


Sharon’s argument relies on the assumption that:

(A) normal levels of unemployment are rarely exceeded
(B) unemployment is not normally concentrated in geographically isolated segments of the population
(C) the number of people who each know someone who is unemployed is always higher than 90 percent of the population
(D) Roland is not consciously distorting the statistics he presents
(E) Knowledge that a personal acquaintance is unemployed generates more fear of losing one’s job than does knowledge of unemployment statistics

My question is: Can you show how you arrived at the correct answer? In particular, I am curious to see the diagram for the argument, the explanations you used to eliminate incorrect answer choices. Are there any special techniques that can be used in “conversation-type” CR.

Sorry, I forgot correctly reference the source:
Source: The official Guide for GMAT Review 11th Edit

I understand the concern with diagramming. Though important, diagramming does not necessarily alert you to the correct answer. Instead, diagramming helps you to understand the text of the argument, so you are better prepared to accurately eliminate incorrect answer choices and eventually deduce the correct answer.

In this argument, Sharon has stated that it is not surprising that 90% of workers know someone who is unemployed. She bases this on a moderate 5% level of unemployment and the estimate that a person knows approximately 50 workers. With Sharon's numbers, any given person would actually be expected to know 2.5 unemployed workers, assuming that ALL UNEMPLOYED WORKERS ARE EVENLY DISTRIBUTED. In other words, there would have to be an equal chance that the 50 workers I know are just as likely to be unemployed as the 50 workers you know.

One strategy I often employ on assumption questions is what I term the "Negation Test." An assumption, by definition, is NECESSARILY TRUE and supports the conclusion. Thus, the negation of the assumption would have to undermine the conclusion. Let's apply this "test" to answer choice (B), our correct answer. Answer choice (B) states unemployment is not normally concentrated in geographically isolated segments of the population . If we "negate" this answer choice, it would state unemployment is normally concentrated in geographically isolated segments of the population . If unemployment were concentrated in "geographically isolated segments of the population," then Sharon's conclusion would not make sense, since personal acquaintance with an unemployed worker would depend on geographic location.

When the negation of an assumption causes the conclusion of the argument to crumble, that assumption (in its affirmative) must be vital to support the conclusion. Normally, this indicates a correct answer choice.

Hope that helps!