#12 - Local, Rule Substitution

[Administrator]

Complete Question Explanation
(The complete setup for this game can be found here: lsat/viewtopic.php?t=4898)

The correct answer choice is (D)

This question stem suspends the second rule and asks you to replace it with an answer choice that results in the same effect. Thus, we need an answer choice that effectively results in a J K relationship.

Answer choice (A) should be eliminated immediately, as it is the Mistaken Reversal of the rule we are seeking to replace. Plus, it is highly unlikely that the correct answer will address just J and K, as those are the two variables in the rule being replaced, and such an answer might be too obvious.

Answer choice (B) addresses the three variables besides J and K, and so there could conceivably be an alignment here that forces a J and K relationship. However, this rule does not imply that J K, and thus it is incorrect.

Answer choice (C) creates a rule that effectively results in one or both of O and K always being assigned an ambassadorship. While this can result in J and K being assigned ambassadorships at the same time, there are also scenarios where J is assigned an ambassadorship and K is not (O-J-L for example), meaning that this answer choice does not equally substitute for the second rule.

Answer choice (D) is the correct answer. This answer results in a rule that appears as follows:

• J N

Of course, the first rule states that one of K or N is always assigned to an ambassadorship. Thus, when combined with this answer choice, when J is assigned an ambassadorship, N is not, and when N is not assigned an ambassadorship, K must be assigned an ambassadorship. Hence, under this answer choice, whenever J is assigned an ambassadorship, then K is assigned an ambassadorship. Therefore, this answer choice is correct.

Answer choice (E) results in the inference that O K, which is clearly different than the second rule.

[catherinedf]

Hi,

I'm looking at the Oct 2011 LSAT, sect 2, logic game 2 - Candidates for Ambassadorships

I'm pretty sure I understand how this game works (grouping), but I'm having trouble with the wording of question 12. What do the mean when they say "which rule would have the same effect in determining the assignment of ambassadorships?" Even if I test all the answers, I'm not really sure what I am testing for...

Thanks for any help!

Catherine

[Adam Tyson]

Catherine,

A question like that is asking you to determine which of the answer choices results in the same diagram and inferences as the rule they want you to replace. In other words, which of these new rules ends up having the exact same effect as the replaced rule? Take a look at answer choice D, and notice that when J is in, N is out. When you couple that with the first rule (you have to have either K or N, but not both), that means when N is out, K is in. Put them together, and you end up with anytime J is in K must also be in, and that's the exact rule you are trying to replace. That's what you are testing for.

Hope that helped! Good luck on the exam.

Adam

[catherinedf]

Thank you Adam! Is this type of logic game question more rare?

Catherine

[Dave Killoran]

Hi Catherine,

This is a relatively rare type of question, but in recent years it has been appearing more frequently, and it has appeared on the last several tests.

The gist of this question is to find the condition that can be substituted for the rule, and that will produce an identical result. So, as you might expect, you first need to isolate the rule that is being removed and examine its effects on the variables. Then, find an answer choice that mimics those effects.

Please let me know if that helps. Thanks!

[netherlands]

Hi there PS,

Can you explain the difference between C and D in this question.

Thank you!

[David Boyle]

Hi there PS,

Can you explain the difference between C and D in this question.

Thank you!

Hello netherlands,

When I try to quote you, oddly enough, it cuts off everything below what you noted above. --Also, it sometimes helps if you mention the month and year of the test. Thanks.

Anyway, as for answer choice C and what you say about the absence of O and K together causing problems: but J-L-N could work, maybe?
Also, if you have O-J-L, then you could have J without K, so choice C doesn't help.

And when for answer choice D you say "J not being with N doesn't for J to require K."; but from rule 1, maybe it does, in that J forces out N, so that K must be there. So, J does require K after all!

By the way, your observations on how to figure out substitution games seem intelligent. Good luck!

Hope that helps,
David

[netherlands]

Oh, ok somehow I totally overlooked the application of the first rule while working the substitution scenarios. If J forces out N, and either K or N must be present then whenever J were in it would absolutely require K.

got it. thank you!

[kristinaroz93]

I am confused with number 12 of this game. The answer is choice D: Jaramillo and Novetzke are not both assigned to ambassadorships. This is based on the explanation that Either K or N is assigned to one of the ambassadorships, but not both. And so when J is chosen, N is not, and when N is not assigned, then K must be assigned. But can't this be a valid answer as well given J and N cannot be together: JOL. This way J and N are not together, but it does not have j&k together, making the answer choice invalid. This is because when I see a double not arrow I always assume either one variable or the other is in, but that it does not exclude both from being out. So Am I wrong here in assuming that both K & N can be out simultaenously?

And so in what scenarios can both variables be out and in what scenarios must one automatically be in when the other is out?

I hope my question made sense.

Best,

Kristina

[jeff.wren]

Hi Kristina,

I'll try to clarify what's going on in this question and why (d) is the correct answer.

The first important point to realize is that the first rule in the game "either K or N, but not both" is really two rules in one. The "either/or" part of the rule means that at least one of K or N must be selected, while the "not both" part means that they cannot both be selected. Combined, the rule amounts to exactly one of K/N is in and one of K/N is out. If you were to diagram out the rule, the "either/or" part would be diagrammed: not K <-|-> not N while the "not both" part would be diagrammed K <-|-> N.

When combined with the second rule (if J, then K) we can make the inference that J and N cannot be selected together because J brings along K, and K kicks out N.

Now q. 12 is asking for an answer that, when combined with the other rules, would produce the same effect as the second rule (J-->K). Answer (d), J and N are not both selected, contains the inference that we made in our setup by combining the first two rules. If we take this statement and link it to the "either/or" part of the first rule, then we can determine that if J is in, the K must be in because if J is in, then N is out, and if N is out, then K must be in (since at least one of K and N is always in from rule 1).

I hope that this helps.

Best,
Jeff