PT69.S4.Q21 - If Skiff's book is published this year

Logic Gainz

Okay people, this is probably one of the hardest LR questions I've ever done, but also why I like talking about it. It's also why I think learning to think in terms of "lawgic" could sometimes make things more difficult. Allow me to explain.

If you give the question a quick read and attempt, the difficulty lies in the fact that the conclusion is a conditional statement with 2 pieces to the sufficient condition - e.g. (A&B) => C. We are given a premise in the form of P => Q, and another that states Q => C. However, in the correct answer choice, the answer states A => P, which is supposed to connect the missing gap.

In the explanation, we're told that the "B" piece in the above sufficient condition is redundant, but how are we supposed to decide when elements are redundant and when they aren't? Typically, when a sufficient condition has two pieces, we NEED two pieces in order to infer the necessary condition. In this question, we don't. Is this supposed to be something we just intuit on test day?

I realize that this post might not make any sense at all so let me know if what I'm asking is hard to follow.

Edit: In short, I'm kind of an idiot. I just realized that B is, in fact, redundant because it's just a random variable tacked on in the conclusion. It's pretty worthless as long as we have that A piece linking us up with that P piece. I didn't realize this until I typed all this up and wasted everyone's time, but I thought I'd just leave this here anyway. Typing up reasoning is gold. I was confused because of where the conclusion is placed in the argument. It jumps out as a premise, hence why I thought that B piece was important.

Admin note: edited title and added link
https://7sage.com/lsat_explanations/lsat-69-section-4-question-21/

lady macbeth

I chose answer choice B during timed practice but during BR went with correct answer choice A. Although this was a hard question, I think question #17 in this section was way harder!!

Logic Gainz

@"lady macbeth" you think so? This must be a "different strokes for different folks" ordeal, because this question along with #18 ripped me a brand spanking new one.

lady macbeth

what!!!! definitely a different strokes kinda thing then. i came to the correct answer choice for #18 during timed practice and didn't circle it for BR. i eliminated D & E right away. for #17, i thought it was way harder due to the attractiveness of choice E which is what I chose.

question 21 about Skiff's book was easy imo. I have to work on timing and pressure and anxiety. I found that all I needed was the time to write out #21 in formal logic, but during timed practice I just chose whatever my eye picked up on and ran. but during BR, i was like, ok ok ok -- this was easy -- i just didn't have the time/headspace to spend another minute on the question and write out the formal logic.

Logic Gainz

Don't get me wrong, I wasn't yawning through #17 or anything, I just had an ah-ha moment while doing that particular one. Regardless, your logical intuition skills sound incredible. Hopefully I'll be on that level one day.