Q22 - On Wednesdays, Kate usually buys some guava

[ilene.molina]

Can someone please give me the breakdown for this one?

Thanks.

[ohthatpatrick]

Question Type: Match the Reasoning

Argument Core:

Conclusion
Kate must sometimes shop at local health food store on Wed's

Evidence
On Wed's, Kate usually buys guava.
Local health food store is only place Kate can buy guava.

Analysis of Core

Looks like a pretty airtight conclusion. How did we get there?

We know that Kate sometimes buys guava and that you must buy guava at a certain place, so we can conclude with certainty that Kate sometimes goes to that place.

PUT IT INTO MORE OF AN ABSTRACT RECIPE
2 premises ... 1 most statement and 1 conditional:
- for most X's (wed's), Y happens (kate buys guava)
- Z (going to local health store) is the only way Y happens

Conclusion:
some X's (wed's) involve Z (going to local health store)

EVEN MORE SYMBOLICALLY, IF YOU LIKE THAT
Most X are Y.
Y --> Z
-------------
Some X are Z



(A)
- Most X's (CD dinners) are Y (prepared in CI kitchen).
- Z (CI teacher) is the only way that Y happens.
Thus, some X's must involve Z.

Looks pretty good.

(B) Strength of language mismatches make this one not seem worth a close read. Both premises are conditional and the conclusion is also conditional.

(C)
- Most X's (CD dinners) are Y (prepared in CI kitchen)
- Z (CI teacher) is one way that Y happens.

We can stop there. Y does not guarantee us of Z. All teachers are guaranteed access to the CI kitchen, but the fact that something was prepared in the kitchen doesn't guarantee us that a CI teacher made it.

(D)
- Most X's (CI teachers) are Y (allowed to use kitchen)
- if it's Z (CD dinner) then it's kinda like Y (prepared in kitchen)

Stop there. Not a true match between the Y concepts. More importantly, Y doesn't guarantee Z.

(E)
Most X's (CD dinners) are Y (prepared by CI teachers)
Z (allowed to use CI kitchen) guarantees kinda like Y (teacher at CI)

Stop there. Not a true match between Y's and Y doesn't guarantee Z.

The correct answer is (A).


One good way to attack this one, if you hate translating these into abstract recipes, is simply to look for another airtight argument.

Only (A) and (B) are valid arguments. Hope this helps.