LR Question 19 Explanation, by LSATHacks
QUESTION TEXT: The conventional process for tanning leather uses…
QUESTION TYPE: Necessary Assumption
CONCLUSION: It costs less to tan leather using biological catalysts.
REASONING: Tanning leather with biological or chemical catalyst costs the same, if we leave out waste disposal costs. But the biological catalysts make less waste, and getting rid of waste is expensive.
ANALYSIS: The reasoning and conclusion are about the costs of using each type of catalyst. They cost the same to use, if we don't include getting rid of the waste.
So waste disposal costs are the only weak area. We know biological catalysts produce less waste. But what if that waste is much more expensive to get rid of? The argument assumes that isn't true.
___________
- If this were negated and leather tanned conventionally was lower quality, then biological catalysts would be an even better idea. Though technically this has nothing to do with cost.
- Who cares about the cost by weight of the materials? We already know that the total costs for using each type of catalyst work out to the same amount.
- It doesn't matter if biological catalysts have always been affordable, or whether they just recently became affordable. Either way, they're cost effective now.
- CORRECT. If you get 20% less waste with biological catalysts, but that waste costs seven times more to get rid of, then maybe biological catalysts aren't such a good idea.
- The second sentence clearly says that the two tanning processes cost the same amount if you leave out waste. That means all other costs are included: labor, machines, materials, etc. If biological catalysts' labor costs are higher, that just means some other cost is lower.
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Answer choices like D are highly ambiguous – what does “significantly more” mean? 5% more? 10% more? the argument clearly states that it biological catalysts produce 20% less waste than alternatives., so even if the disposal costs 10% more gram for gram, that’s still a 10% savings, supporting the argument’s main conclusion.
Any tips for navigating this ambiguity??? As far as I can tell the negation test fails for answer choice D due to ambiguity around the phrase “significantly more”
The idea here is that the phrase “significantly more” could encompass all of these values. It is because this phrase is somewhat ambiguous that we cannot rule out the possibility that if the cost is “significantly more” with “significantly more” denoting a total cost that outweighs the benefit of a 20% reduction of total waste produced, that the argument requires this answer choice, i.e. if “significantly more” did mean this, then the argument would fall apart.