LSAT Question Explanation
PT 105, Section 1, Question 9
Sufficient AssumptionArgument structure
Peeled wild potatoes are at least as safe to eat as unpeeled domestic potatoes that are the same size.
Domesticate potatoes have very little solanine, but wild potatoes can have enough solanine to be dangerous. Most of the solanine in potatoes is in the skin.
Explanation
This conclusion certainly isn't supported. We don't know if a peeled wild potato would have more, less, or equal solanine compared to a domestic potato.
For example: what if a peeled potato has 10 grams of solanine, 6 of which are in the skin. And a domestic potato has 1 gram of solanine. This situation would be compatible with the evidence. Peeling the wild potato would mean it would be left with 4 grams of solanine, still more than the domestic potato, and potentially at toxic levels. This disproves the conclusion, that peeling the wild potato would make it just as safe as the domestic potato.
Because this is a Sufficient Assumption question, we need an answer choice that shows that a peeled wild potato has the same or less solanine than an unpeeled domestic potato, fixing the flaw and proving the conclusion.
Answer choices
This is not enough to prove that peeling wild potatoes makes them just as safe as domestic potatoes. For all we know wild potatoes could have 100 times as much solanine as domestic, and maybe only slightly more than half is in the skin.
This doesn't help prove the conclusion because the conclusion is about peeled wild potatoes. We need to know that there isn't more solanine in a peel-less wild potato than a domestic potato.
Perfect. This says there is no more solanine in wild potatoes once they've been peeled than in unpeeled domestic potatoes, proving the conclusion.
This doesn't prove that wild potatoes are just as safe once peeled as domestic are. It tells us nothing about solanine levels, and nothing about wild potatoes.
The conclusion is specifically about potatoes of the same size, so this doesn't matter.