October 2008 PT, Section 1 (LR), question #15

[brittany1990]

After reading the stimulus and question stem, I recognized that it was a MBT question. I prephrased that Zack's Coffeehouse offers half-priced coffee almost every Wednesday. After reading the answer choices, I eliminated A-C and was left with D and E. D almost exactly matched my prephrase but I did not like the "if not all." I thought that phrase didn't pass the fact set since it said in the stimulus "almost every Wednesday" so I chose E.

May you please explain why D is better than E?

Thank you!
Brittany

[Nikki Siclunov]

The stimulus contains two statements, which can be diagrammed as follows:

Wednesday Free Poetry

Free Poetry Half-Priced Coffee

Combined, they produce the following chain:

Wednesday Free Poetry Half-Priced Coffee

The inference we can draw is:

Wednesday Half-Priced Coffee

This is consistent with answer choice (D). "Most" means "more than half," i.e. we know that Zach's offers half-priced coffee on more than half of all Wednesdays. This is the same as saying "most if not all Wednesdays."

It is unclear whether there are any Wednesdays on which half-priced coffee is not offered, which is why (E) is incorrect. "Most" includes the possibility of "all," so that it is possible - though not certain - that there is half-priced coffee every Wednesday.

This is Formal Logic, which is explained as a Virtual Supplement to Lesson 8 of our Full-Length LSAT course.