Manhattan Prep Instructor
Joined: 22 Mar 2011
Posts: 2645
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GMAT 2: 780 Q50 V50
Re: Nearly all adults in the community of Amaretti, including pregnant wom
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30 Jun 2022, 15:21
For C, we don't have to assume that older children are smarter. We just have to acknowledge that this is another factor that may account for the difference we're seeing. After all, we also don't know that maternal fasting leads to less capable babies--that's the issue! Any other substantial difference between the November kids and the rest could turn out to be the causal factor. If the November kids are always the oldest in their class, then that definitely counts as a substantial difference. C could just as easily have described some other difference that *might* affect performance, such as that only the November kids benefited from additional parental care as their parents stayed home to fast during eight of the crucial early weeks of life.
(We shouldn't have to bring in any significant real-world knowledge to get these, but it's worth pointing out that kids do grow and change quite rapidly in the early years, so an advantage of months is much more significant in first grade than it is later.)
As for E, this might weaken if we didn't have the 2% figure. If ~25% of kids were born in November, then it's no surprise that ~25% of them show up in any segment of the population. However, that makes it all the more striking that November kids make up only 2% of the bottom fifth. So E reduces the importance of one premise, while proportionally increasing the importance of another. We're still left wondering what caused that 2% figure, and we haven't been given any information that undermines the author's explanation.