Logic Games: "either/or" rule...

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jesuis
Posts: 42
Joined: Sat Jul 25, 2009 4:56 am

Logic Games: "either/or" rule...

Postby jesuis » Tue Apr 20, 2010 2:01 pm

Can anyone clarify what "either or" implies when given as a rule...

Example: [see Logic Games Bible, pg. 153--Advanced Linear Games: Game #2 from October 2004 Q13-17]

Rule: "The site visited third dates from a more recent century than does either the site visited first or that visited fourth"

Does this rule mean that the site visited 3rd dates more recent than 1st or 4th but not both, so that it's more recent than one but not the other--either contemporary or older than the other?

Or does it mean that 3rd site visited is more recent than both 1st and 4th site visited?!

Based on the explanation of this problem, the rule implies the latter (3rd more recent than both 1st & 4th), but that doesn't make sense to me, given the "either/or" wording of the rule!

I apologize if this seems to abstract without more information on the problem-let me know and I'll post more or PM...

Basically my question is that, when "either/or" is used in a rule to relate 3 variables (e.g. A is bigger than either B or C) does the "either/or" imply that A must be bigger than both B & C, or that A is bigger than one (B or C) but not both (B & C)?!?

hmm, after writing this out, I think I realize that either/or does imply that the action (A is bigger) applies to both (than B & C)... but I would love to hear what you all think!

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longdaysjourney
Posts: 278
Joined: Wed Apr 14, 2010 12:47 pm

Re: Logic Games: "either/or" rule...

Postby longdaysjourney » Tue Apr 20, 2010 3:29 pm

S3(sub Century) > S1(sub Century)/S4(sub Century).

Change Either/or to Both/and in this particular instance.

The easiest thing to do would be to put a "10" not law under site 3 and an "8" not law under 1 &4.

jjlaw
Posts: 299
Joined: Thu Dec 31, 2009 1:43 pm

Re: Logic Games: "either/or" rule...

Postby jjlaw » Tue Apr 20, 2010 5:58 pm

jesuis wrote:
Basically my question is that, when "either/or" is used in a rule to relate 3 variables (e.g. A is bigger than either B or C) does the "either/or" imply that A must be bigger than both B & C, or that A is bigger than one (B or C) but not both (B & C)?!?

hmm, after writing this out, I think I realize that either/or does imply that the action (A is bigger) applies to both (than B & C)... but I would love to hear what you all think!


It could be either B or C, or both B and C. "Either/or" in LSAT land means "either" or "both".

jbaz
Posts: 2
Joined: Wed Aug 18, 2010 4:56 am

Re: Logic Games: "either/or" rule...

Postby jbaz » Wed Aug 18, 2010 5:43 am

I know exactly what you are asking cause I spent forever trying to figure out the same thing.
The convoluted wording is what makes this so hard to figure out and the fact that we are looking intently for different ways for the question to mislead us.

Take this sentence for example which pretty much has the same structure.

Obama has much greater personal appeal to independent voters than does either McCain or Clinton.

Here it's a lot easier to see that it means both McCain and Clinton. This is because of the use of "than does either". When ever this wording is used then the following will mean both of those things. When you use the word "either" you have to use the word "or" because it is just proper grammer which is also why "both" is used with "and". The use of either usually implies one or the other but when you see it used in "than does either" it means both.
Here are some examples of the ways either/or and both/and are usually used:

Meaning: one or the other (either/or)
A is (comparative adjective) than either b or c (in relation to)
A is in either b or c (location)

Meaning: both (both/and)
A is (comparative adjective) than b and c (in relation to) (this is also where "than does either" fits)
A is in b and c (location)

hope this helps!




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