Argument Completion Drill Question? Forum

[LSAT_Padawan]

Can someone explain how you come up with the conclusion "U"?

P: W or X ---> Y and Z
P: Not U ---> X
P: Not T
__________________________
C: U

Thank you for your enlightenment!

[FreeGuy]

Here are a few sufficient assumptions for this argument:

Not Y
Not Z
Not X


Because:

Not U ---> X ---> Y and Z

so, the contrapositive is:

Not Y or Not Z ---> Not X ---> U


The Not T is irrelevant.
The W in the first premise is irrelevant.

[LSAT_Padawan]

FreeGuy, thank you for your input. I understand your explanation and how you came to conclude "U" but how did you know that "W" and the 3rd premise "not T" were irrelevant? That's where I struggle because I'm trying to incorporate all the elements.

[FreeGuy]

X is the only variable repeated in the premises.

It connects "Not U," "Y," and "Z" together.

"Not T" and "W" are not connected by X.

Sometimes, certain elements in the premises won't matter. Stimuli can contain useless info.