According to a 1980 survey, ten percent of all United States

Question

According to a 1980 survey, ten percent of all United States citizens over the age of sixteen are functionally illiterate. Therefore, if the projection that there will be 250 million United States citizens over sixteen in the year 2000 is correct, we project that 25 million of these citizens will be functionally illiterate.

Which of the following, if true, would most weaken the conclusion drawn by the author of the passage above?

(A) The percentage of high school graduates who do not go on to college has grown steadily over the past two decades.
(B) From 1975 to 1980 there was a three-percent decrease in the rate of functional illiteracy among United States citizens over the age of sixteen.
(C) Many United States citizens included in the 1980 survey would be also included in a survey conducted in the year 2000
(D) Surveys that are improperly designed usually provide inaccurate results.
(E) In 1980 sixty-five percent of all United States citizens were over the age of sixteen.

jainu · Answer

B it is...
I eliminated it to A and B. Now A actually carries no signficance because it does not weaken the conclusion because it does not talk about the specific age group(above sixteen). Hence B...

priyankurml · Answer

IMO B.

if the pattern does not follow, conclusion will not perpetuate from pattern.

IanStewart · Answer

Yes, certainly should be B here. We can see from B that illiteracy has already been trending downward leading up to 1980; this suggests that the illiteracy rate is not constant, and that there is no reason to expect a 10% illiteracy rate in twenty years.

icandy · Answer

While I agree that other choices do no make sense, this one needs us to estimate what happens in 20 years based on last 5 years. Even if the downward trend is true (as said in the gmat Q's) it does not necessarily mean that the trend in the 20 years will NOT remain constant. Who know? huh?

IanStewart · Answer

Bear in mind that we only need to weaken the conclusion - that is, cast some doubt on its validity. We don't need to do anything nearly as strong as disproving the argument. If the literacy rate hasn't been constant over the last five years, then it's reasonable to think that the rate could be quite different in twenty years. The projection in the argument assumes a constant literacy rate; if the literacy rate is not constant, the projection isn't likely to be correct. As you say, there's no way to be sure what the literacy rate will be in twenty years - the 25 million may turn out to be correct after all - but we have more reason to doubt that if we know that B is true.

VerbalBot · Answer

Automated notice from GMAT Club VerbalBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

According to a 1980 survey, ten percent of all United States

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

According to a 1980 survey, ten percent of all United States

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards