In 1980, Country A had a per capita gross domestic product (GDP) that was $5,000 higher than that of the European Eco...

Mehran on July 23, 2018

Hi @smilde11, thanks for your post.

Well, let's start - as always - with the stimulus. This is an argument. The conclusion is "the average standard of living in Country A must have risen between 1980 and 1990." Why? The premises are (1) that in 1980, Country A had a per capita GDP that was $5k higher than that of the EEC; and (2) by 1990, the *difference* had increased to $6k (when adjusted for inflation).

Please notice that the conclusion makes an absolute claim about the average standard of living in Country A, but the given premises are about relative information (Country A relative to the EEC). There is a gap in the stimulus. This argument could be stronger.

Well, lo and behold! This is a Strengthen with Necessary Premise question. The correct answer, (D), is necessary for the conclusion. If you negate (D) - "the per capita GDP of the EEC *was* lower than $1k in 1990 than it had been in 1980" - then the argument in the stimulus falls apart.

(A) is entirely irrelevant, because it does not speak to the link between the premises and the conclusion. Why are we talking about population increases at all? The conclusion is about a rising average standard of living, and the premises have to do with relative per capita GDP. Answer choice (A) does not fit in here.

Likewise, (B) is entirely irrelevant. The conclusion is only about the "average standard of living" in Country A. We don't even know if the per capita GDP of the EEC declined - much less that the standard of living there did so. This statement does not bridge the gap between the premise and conclusion in the stimulus; thus, it is not the missing necessary premise needed to strengthen the argument.

Hope this helps! Please let us know if you have any additional questions.