Bunuel
Colfax Beta-80 is a rare genetic defect found primarily in people of Scandinavian descent. Over 97% of known carriers of this defect have are citizens of, or are direct descendants of immigrants from, Denmark, Norway, and Sweden. People who carry the Colfax Beta-80 defect are at substantially higher risk for contracting Lupus and related autoimmune diseases.
Assuming the statements above are true, which of the following can be inferred from them?
(A) People from Denmark are at a higher risk for Lupus than people of other, non-Scandinavian countries.
(B) Genetic engineering that eradicated this genetic defect would constitute a de facto cure for Lupus.
(C) Find a cure for Lupus would eliminate most of the health threats associated with the Colfax Beta-80 defect.
(D) A person not of Scandinavian descent born with the Colfax Beta-80 defect is more likely to contract Lupus than is a Scandinavian who is born without this defect.
(E) The majority of people who contract Lupus are either Scandinavian or of Scandinavian descent.
Magoosh Official Explanation:
The prompt tells us that Colfax Beta-80 is a genetic defect. Most of the folks who have this defect are Scandinavian, but we don’t know what percent of Scandinavians have this defect. It may be a substantial portion, but that’s unlikely because the defect is “rare.” Much more likely: there only be a couple hundred people in the whole world who have this defect, and 97% of this couple hundred are from Scandinavia —- a large percentage among those with the defect, but not a large percentage among the Scandinavian population as a whole. A couple answer choices conflate these two percentages.
Anyone with this defect is at higher risk for Lupus and other autoimmune diseases.
(D) is the credited answer. This more or less restates the information of the last sentence. Anyone with this defect (Scandinavian or not) has a substantially higher risk of Lupus compared to anyone without the defect (Scandinavian or not).
(A) & (E) play on the misunderstanding about what the 97% implies. Most folks with this genetic defect are Scandinavian, but that doesn’t imply that most Scandinavian people have this defect. People with the defect are at higher risk for Lupus, but that doesn’t mean large sections of the Scandinavian population are at risk for Lupus.
(B) is wrong because, while we are told this genetic defect causes susceptibility to Lupus, we don’t know what other factors might cause or contribute to Lupus. Just because we eliminate this one factor does not mean we would eliminate everything in the world that could possibly contribute to the onset of Lupus.
(C) is wrong because, while we are told this genetic defect causes Lupus, we are also told it causes other autoimmune diseases. Even if we had a cure for Lupus, these other autoimmune diseases would still poses health threats to carriers of the defect.