Setup and Rule Diagrams

[Steve Stein]

Hi,

Thanks for your response--you got it; if the test makers say that there are three possibilities, you should not assume that they will all be represented unless that is specified.

I hope that's helpful! Please let me know whether this is clear--thanks!

~Steve

[reop6780]

I have some difficuliy in regard with the language of the game set.

The very last rule which states that the third site dates from a more recenet century than EITHER the first site OR the fourth.

Since it did not say the 3rd site is more recent than BOTH the 1st AND the 4th, I only assumed that the 3rd site cannot date from 8th century.

However, according to the explanation on pg 156, "the first and fourth sites cannot date from the 10th century."

How can you infer this when it is possible that the 3rd site is more recent than only one of two sites, the 1st and the fourth?

- for example, the 1st: 8c the 3rd: 9c, the 4th: 10c .

The rule states that the 3rd is more recent than either one of them not necessarily both.

Additionally, when it says in the stimulus that "each dates from the 8th, 9th, or 10th century," it does not necessarily mean that at least one of ALL (8,9,10) must be present, does it?

(It's always confusing)

[David Boyle]

I have some difficuliy in regard with the language of the game set.

The very last rule which states that the third site dates from a more recenet century than EITHER the first site OR the fourth.

Since it did not say the 3rd site is more recent than BOTH the 1st AND the 4th, I only assumed that the 3rd site cannot date from 8th century.

However, according to the explanation on pg 156, "the first and fourth sites cannot date from the 10th century."

How can you infer this when it is possible that the 3rd site is more recent than only one of two sites, the 1st and the fourth?

- for example, the 1st: 8c the 3rd: 9c, the 4th: 10c .

The rule states that the 3rd is more recent than either one of them not necessarily both.

Additionally, when it says in the stimulus that "each dates from the 8th, 9th, or 10th century," it does not necessarily mean that at least one of ALL (8,9,10) must be present, does it?

(It's always confusing)

Hello reop6780,

Especially in the context here, I believe that "A is more [whatever] than either B or C is" tends to mean that A has more (of whatever) than BOTH B and C. "Either/or" is confusing because usually, on the LSAT, "Either A or B", as in conditional reasoning, tends to mean "A, or B, or both". But to say "A is more [whatever] than either B or C is" tends to mean, again, that A has more than both of the other folks.
An example: "Bob is taller than either Joe or Bill." In common parlance, that would usually mean that Bob is taller than both of them. It would be strange if someone meant, "Bob is taller than Joe, but not Bill", since he could just have said "Bob is taller than Joe". Does that make sense?

Also, "each dates from the 8th, 9th, or 10th century" may not *logically* imply that at least one of each of those centuries has to be present, that is true. (Though, don't be surprised if each one appears.)

Hope this helps,
David

[reop6780]

Thank you so much!

[gab123511]

Hi, just a quick question about rule 3 in that "Exactly one of the sites was discovered by Gallagher, and it dates from the 10th century." The explanation in my book says that you use the contrapositive to infer that any site that dates from the 8th or 9th century was not discovered by G and indicate it on the diagram...however I thought that you only use the contrapositive for conditional rules???? Like if it said "if one of the sites was discovered by Gallagher, then it dates from the 19th century" then that would prompt you to invert and use the contrapositive there...please help thanks!

[Clay Cooper]

Hi gab,

Thanks for your question.

You are correct that the term contrapositive only really makes sense as it relates to conditional statements. However, the rule you mentioned can be interpreted as a conditional statement. In other words, one part of the statement that there is only one site that was discovered by Gallagher and it dates from the 10th century could be expressed like this:

If any site was discovered by Gallagher, it dates from the tenth century.

or

discovered by Gallagher 10th

which would yield the contrapositive:

~10th ~discovered by Gallagher.

Yes, there is another bit of information included in the rule you mentioned - that there is only one such site - and it is certainly important, but don't let it distract you from the conditional nature of the rule.

I hope that helps!

[JaneBlueSky]

I got all answers correct by luck because my final setup is different from Dave's. I don't have Bible book but have three full lesson books. I don't remember I saw this game in my three text books. Could you advise?

My confusion is with G and 10th century. To combine Rule 3 and 5, I came up the following setup:

8/9 9 10 9 9
O/F F G F F

In comparion with Dave's final setup, it seems both discoveries by F and O can be dated to 10th Century in addition to the Rule 3 G -> 10th century?

What I might have missed here? Did I assume .? If we add "respectively" to the restrictions as :

-F,G,O - and each dates from the 8th, 9th, or 10th century respectively.

would my setup be correct?

Thanks.

Jane

[Emily Haney-Caron]

Hi Jane,

Thanks for the question! I think something got cut out from your posting, and I want to make sure I understand exactly what you're asking before I respond. Do you mind looking over your question and filling in that blank there?

Thanks!

[JaneBlueSky]

in my interpretation of the conditions, I came up with G dated 10th century, F dated 9th century and O dated 8th century.

I meant I assumed G 10, F 9 and O 8. In Dave's setup, it shows G,F and O all can be dated 10th century.

[Emily Haney-Caron]

Hi Jane,

Thanks for clarifying! Let's walk through the rules here, to see if it clears things up for you.

Rule 1 - pretty straight-forward
Rule 2 - Again, easy to diagram/understand
Rule 3 - G 10 (and 10 G); also note there is exactly 1 G. This also means that 2 can't be G (because it is 9).

Rule 4 - 8 O (and O 8)

Rule 4 also means that sites 4 and 5 both can't be 8 (because of rule 2).

Rule 5 - This one is trickier. It looks like 3 could be 9 or 10. However, 4 is not 8 (see above), so 3 is going to have to be 10, and 4 is going to have to be 9. 1 cannot be 10, which also means it cannot be G. If 4 is 9, it can't be G, and it already couldn't be O, so we know 4 has to be F.

I think what might have happened is that you might have had a mistaken reversal of Rule 4; note that it is 8 O, but NOT O 8. Similarly, G 10 but NOT 10 G. Getting that mixed up could cause the issue you had with thinking there were more limitations than there actually are. Take a look, and see if that helps. If not, see if you can walk us through how you got to F 9 and O 8.