#6 - Global, Rule Substition
Posted: Tue Oct 02, 2018 1:23 pm
Please post your questions below!
Get expert LSAT preparation and law school admissions advice from PowerScore Test Preparation.
https://forum.powerscore.com/
AWash180 wrote:Hello!
I originally picked B for this question because if R is 1st then it is true that T must be 7th since there are only two places for T to go according to the 3rd rule.
Is E the correct answer because T must be the sufficient condition and R must be the necessary condition in order to replicate all of the impacts of the 4th rule?
Thanks!
I wrote rule 4 & combined inference from rule 3 as:That is absolutely correct.
T NOT in 1 (this means T is in 7 because of rule 3) Rule in 1
CP: R not in 1 (R open to go anywhere else) T in 1
For this reason, I understood that the answer choice to rule sub. question had to have the same effects as T being in either 1 or 7.This is already a bit of an issue - what you're saying here is the 3rd rule. We're substituting for the 4th rule. The 3rd rule will always be in play anyway, so there's no need to substitute for it or to choose an answer that has the same effect as it. Any answer we pick will always be subject to the 3rd rule, which we can still use, so this is not a useful way to evaluate answers.
With this analysis, I had (C) & (D) as answer contenders:As before, you're evaluating the answer by whether it puts T in 1 or 7. That's not the rule we're trying to replace. For a specific problem with this answer, note that when R is not 7, T certainly doesn't have to be 7. T could be 1, with R anywhere else! Answer choice (C) forces T to be 7 anytime R isn't, which isn't true.
(C) Diagrammed: R NOT 7 (R open to go anywhere else) T in 7.
CP: T NOT IN 7 (this means T is in 1 because of rule 3) R in 7
This forces T to be in 1 or 7.
(D) T IN 7 R NOT IN 7This isn't what answer choice (D) says. It's:
CP: R IN 7 T NOT IN 7 (this means T is in 1 because of rule 3)
This also forces T to be in 1 or 7.
Did I misunderstand the meaning of rule 4? I don't understand why (C) & (D) are incorrect.Now I've dealt with that. Moving on:
I thought (E) introduced a new condition as if R isn't in 1, R can go anywhere (didn't want to make a mistaken reversal of R's limitation). What makes (E) the correct answer choice?Nothing about answer choice (E) prevents R from going anywhere the original conditions allow. The original conditions force R to be 1 if T is not 1. So answer choice (E) is certainly true: