P: W → XP: not Y → not XP: ?C: W → Z

Flavio March 15, 2016

How is B wrong?

The missing premise has to be Y âž¡ï¸Z Not Z âž¡ï¸not Y

Replies

Create a free account to read and take part in forum discussions.

Already have an account? log in

Mehran March 17, 2016

@Flavio the contrapositive of "Y âž¡ï¸ Z" is "not Z âž¡ï¸ not Y" so they are logically identical in meaning.

Hope that helps! Review our Sufficient & Necessary lesson if you need a more in-depth refresher of these concepts.

Flavio March 18, 2016

Yes @Mehran I picked this answer choice (C), but I noticed that it marked it wrong and instead marked B as the correct answer, so I figured it might've been an error.