Zack's Coffeehouse schedules free poetry readings almost every Wednesday. Zack's offers half–priced coffee all day on...

Matthew on February 3, 2015

Help

Please explain why D is better than E.

3 Replies

Melody on February 3, 2015

This is a Must Be True Question. Thus, the correct answer should be 100% supported by the passage. (D) is better than (E) because answer choice (D) is 100% supported by the passage, whereas (E) is not.

Let's diagram!

"Zack's Coffeehouse schedules free poetry readings almost every Wednesday."

So "almost every" is a majority, which we know is "most." So the statement above is saying, on most Wednesdays, Zack's Coffeehouse schedules free poetry readings. We can diagram like so:

Q1: W-most-PR
PR-some-W

"Zack'a offers half-priced coffee all day on every day that a poetry reading is scheduled."

So, if a poetry reading is scheduled, Zack's offers half-priced coffee. We can diagram like so:

P1: PR ==> HPC
not HPC ==> not PR

We know that when the right-hand side variable of a quantifier statement is the same as the sufficient condition of a Sufficient & Necessary statement, then we can connect them. So, we can connect Q1 to P1 like so: W-most-PR ==> HPC to conclude: W-most-HPC, i.e. on most Wednesdays, Zack's will have half-priced coffee.

This deduction is basically what answer choice (D) tells us: "Zack's offers half-priced coffee all day on most if not all Wednesdays."

Answer choice (E) states: "On some Wednesdays Zack's does not offer half-priced coffee all day."

Well, the information in the passage never tells us when Zack's does NOT offer half-priced coffee all day. We merely know that Zack's offers half-priced coffee all day on every day that poetry reading is scheduled. This does not mean that if there isn't a poetry reading scheduled that Zack's will most definitely not offer half-priced coffee all day. We do not have adequate information for this.

Just because we can infer that on most Wednesdays Zack's offers half-priced coffee all day, we cannot infer that on some Wednesdays Zack's does not offer half-priced coffee all day. Remember, a quantifier statement does not have a contrapositive, we can merely reverse the variables and make a "most" into a "some," or vice versa.

So, we only know: W-most-HPC, or HPC-some-W

And remember, "most" means "more than half." So, technically--in our LSAT world--the statement "on most Wednesdays, Zach offers half-priced coffee," could technically mean "on all Wednesdays, Zach offers half-priced coffee." This isn't a Could Be True Question. We are not looking for an answer that could be true. We are looking for the answer choice that must be true, i.e. the answer choice that is 100% supported by the passage.

Thus, since (D) must be true, whereas (E) could be true, (D) is the correct answer.

Hope that clears things up! Please let us know if you have any other questions.

Matthew on February 4, 2015

What lesson plan would help me improve on these types of questions?

Melody on February 5, 2015

You should make sure to review the lesson on Must Be True Questions and Quantifier Questions.