P: not C → BP: ?C: A → C

Ccurtis3178 May 21, 2016

Can't figure these out

Nearly every time I get these questions wrong. I always end up choosing the reverse of the correct answer so for example A->not B I choose B->not A What am I missing? I read the explanations and see you reverse the initial information given. I write them out and try to understand what I'm not understanding but something is missing from the explanation for me to make sense of it. If I want to get the question right I know all I have to do is reverse my initial answer but I don't understand why.

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Mehran May 24, 2016

@Ccurtis3178 this is an important point to clarify.

There cannot be two correct answers so this situation will never appear on the LSAT.

Using your example:

A âž¡ not B
B âž¡ not A

These statements are logically identical so if both were to appear as answer choices, there would be two correct answers.

Notice here the correct answer is (A), i.e. B âž¡ not A, but also notice that there is no answer choice with "A âž¡ not B."

Hope this helps! For a more in-depth discussion of these concepts, please watch our video lesson on Sufficient & Necessary conditions.