https://classic.7sage.com/lsat_explanations/lsat-60-section-3-question-17/

Any food that is not sterilized and sealed can contain bacteria

JY’s translation: /Sterilized or /Sealed -> can contain bacteria

Jy mentions DeMorgan’s law to reach the translation.

Could somebody explain how the translation works this way?

I initially translated the statement as: /Sterilized and Sealed -> can contain bacteria

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6 comments

  • Saturday, Jul 23 2016

    I think it would take a lot of mental gymnastics to read "any food that is not sterilized and sealed" to mean anything other than "not (sterilized and sealed)", especially when you know that the statement was made by someone who writes professionally and for clarity (like an LSAT writer).

    They'd say "any food that is sealed but/and not sterilized" or "any food that is not sterilized before being sealed" or "any food that is not sterilized and IS sealed".

    English is my second language, so I spent a lot of time thinking about how people use words in sentences, and that's just not the right pattern of phrasing for your secondary interpretation. I keep reading it trying to get it to mean (not sterilized) and (sealed), and somehow it always ends up sounding like a foreigner in an (offensive) funny skit.

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  • Saturday, Jul 23 2016

    You need to use context to disambiguate the scope of the negation. For this question, the second sentence clarifies the scope by saying "Once sterilized and properly sealed, **HOWEVER**, it contains no bacteria." The "however" links together the first and second sentences, and because we see that "sterilized and properly sealed" are together in the second sentence, we're able to figure out that the two are together in the first sentence as well. Thus, the negation in the first sentence takes wider scope over the conjunction, i.e. not(sterilized and sealed).

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  • Friday, Jul 22 2016

    I see what you're saying. Interesting. So it could potentially read:

    Any food that is not (sterilized and sealed)

    or

    Any food that is (not sterilized) and (sealed)

    How do we know to distribute the "not" across the "and?"

    Not sure, to be honest. Any linguists out there?

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  • Friday, Jul 22 2016

    Basically..

    Any food that is not sterilized and sealed can contain bacteria

    Any food that is sealed and not sterilized can contain bacteria

    Aren't these two equivalent statements?

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  • Friday, Jul 22 2016

    How do we tell 'not' here applies to both 'Sterilized' and 'Sealed'?

    Shouldn’t the statement be ‘Any food that is not sterilized or not sealed can contain bacteria’?

    I'm still confused...

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  • Friday, Jul 22 2016

    You apply DeMorgan’s Law when taking a contrapositive. The correct DeMorganized version would be:

    /can contain bacteria —> Sterilized and Sealed

    So you’re basically taking the contrapositive, business as usual: Negate, and switch sufficient/necessary. DeMorgan’s law deals with the and/or issue by just switching it around when you take the contrapositive.

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