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Logic question

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Logic question

by layzzer » Wed May 12, 2010 3:47 pm
Hi I have been reading critical reasoning study guide for LSAT because i hear it's good to have that under your belt as practice. So this might be strange to some/most of you.

S <-- T some U --> V

some T's are U's
All U's are V's
All T's are S's

and you get the diagram above, now the inference part.

by working logic math, one inference possible is some S's are V's

S some V

I don't quite see how..

I understand one can get some S's are T's and Some V's are U's, but I'm missing that last step connecting S's and V's.

Help anyone?

Thanks
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by saurabhmahajan » Thu May 13, 2010 4:11 am
lets start from bottom:
All T's are S's
that means Some S's will be U's (since Some T's are U's and all T's are S's)
therefore,some S's are V's (since all U's are V's)


or

T=S
some T=U...therefore some S=U.
U=V
Therefore some S=V

Am i correct ?
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by layzzer » Thu May 13, 2010 6:46 am
I was working on this last night and I think i have it, so

S <-- T some U --> V

so since U some T --> S, I just reverse the order, it's just going from U to S

that means U some S since some U are T and all T are S, so some U are S and also some S are U since the some relationship goes both ways, that is what I was forgetting.

S some U --> V, so some S are U and all U are V, so some S are V

S some V.
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