Logical ReasoningDifficulty: Easy

PT7 S1 Q2 Explanation

Bevex, an artificial sweetener used

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsNecessary Assumption

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Stimulus

Bevex, an artificial sweetener used only in soft drinks, is carcinogenic for mice, but only when it is consumed in very large quantities. To ingest an amount of Bevex equivalent to the amount fed to the mice in the relevant studies, a person would have, to drink For that reason, Bevex is in fact safe for people.

What this question is testing

Necessary Assumption

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
2.

In order for the conclusion that Bevex is safe for people to he properly drawn, which one of the

Answer choices

  1. Opposite (if anything)1% picked this

    Cancer from carcinogenic substances develops more slowly in mice than it

    This makes it sound like humans are more sensitive to carcinogens than mice are, which actually weakens the argument. The author is assuming that the amount a human would have to ingest to be harmed is at least as great as the amount a mouse had to ingest to be harmed, and this answer actually undermines that assumption.

  2. Out of Scope: Other Food Additives2% picked this

    If all food additives that are currently used in foods were tested, some would be found to

    The carcinogenic properties of other food additives for mice is irrelevant to this specific argument about Bevex.

  3. Correct94% picked this

    People drink fewer than 25 cans of Bevex- sweetened soda

    Why this is right

    If we negated this and said, "People do drink 25 or more cans a day," the conclusion would fall apart because it means they are at risk of ingesting harmful levels of Bevex, much like the mice were exposed to in the studies. This would allow us to argue that Bevex isn't safe for people. The author presented a rule, "If you're drinking less than 25 cans per day, then you're not ingesting an amount equivalent to the harmful amount we fed the mice." But the author never triggered this conditional by asserting, "And people definitely drink less than 25 cans per day".

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

  4. Out of Scope: Health Benefits1% picked this

    People can obtain important health benefits by controlling their weight through the use of artificially

    Whether Bevex could have health benefits through weight control is completely beyond the scope of what the author is trying to prove. She is merely trying to convince us it's safe, i.e. not-harmful. She isn't trying to convince us it's beneficial.

  5. Irrelevant Quality3% picked this

    Some of the studies done on Bevex were not relevant to the question of whether or not Bevex

    This is trying to bait people into inferring something from a premise. The author referred to "the relevant studies", so this answer is suggesting that this implies that there were "irrelevant studies" as well. This has nothing to do with our conclusion. By "relevant studies", the author means "in the studies where we fed Bevex to mice". If there were other studies done on Bevex, does it make any difference to the author whether those studies were or weren't relevant to people? No.

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