Sufficient and Necessary Problem Set #4

[cgrosinger]

Hi

i would greatly appreciate you could post more specific details why/ how the correct solution to this particular problem is properly diagrammed

i am having great difficulty understanding the exact diagramming steps


thanks in advance for your help

[Dave Killoran]

Hi Cgrosinger,

Thanks for the message.I'll try to clarify a bit more on my explanation.

The first sentence of the stimulus can be diagrammed as: IMP --> GS
The second sentence of the stimulus can be diagrammed as: GS --> SL

So, far, that is what you see in the book However, at that point, because GS is necessary in the first sentence and sufficient in the second sentence, that can actually be joined together to create one continuous chain: IMP --> GS --> SL

So, from that, we know that IMP --> SL. In this sense, we have combined and reduced the terms in the first two sentences, but because they connect logically, that is ok to do.

Answer choice (A) is just the contrapositive of that reduced phrase we just discussed, IMP --> SL. Therefore, it is the correct answer.

Please let me know if that helps. Thanks!