LSAT 128 | Section 2 | Logical Reasoning: Q3

LR Question 3 Explanation

QUESTION TEXT: Agriculture researcher: Because of its slow decomposition …

QUESTION TYPE: Flawed Reasoning

CONCLUSION: Farmers should use a mix of paper and manure rather than either alone.

REASONING: The mixture of paper and manure decomposes faster than paper alone, costs the same as paper, and has been shown to significantly reduce soil erosion.

ANALYSIS: The researcher assumes that because the paper-manure mixture was effective in reducing soil erosion, it must be better than both paper and manure alone. However, the evidence only establishes it’s better than paper alone – not that it outperforms manure by itself.

We know that paper alone is bad at preventing soil erosion, that the mixture decomposes faster than paper alone, and that paper and manure cost about the same. These points all explain why using only paper is a bad idea. But they don’t give any reason to believe that manure alone wouldn’t work just as well as (or even better than) the mixture.

In other words, the flaw is that the argument never proves the mixture is superior to manure alone, yet it concludes that farmers would be better off using it.

___________

1. The argument doesn’t depend on whether paper alone contributes to soil erosion. It only states that paper is ineffective as a mulch.
2. It already establishes that the mixture is better than paper alone. The missing evidence is about how it compares to manure alone.
3. CORRECT. The argument assumes that the mixture is superior to manure alone, but no evidence is given for this. If manure alone is just as effective, the conclusion that farmers would be “better off” using the mixture would not follow.
4. The argument doesn’t address nor claim that the mixture is better than ALL OTHER methods to prevent soil erosion – just that it is better than using paper or manure alone.
5. The conclusion is that the paper-manure mixture is better than paper or manure separately. This answer is about comparing paper to manure directly, which is not a comparison the argument makes.