Diagram

[cc4me19]

I figured this problem out and I understand it and the answers, I just want to see how ya'll set it up, because I am pretty sloppy which causes me to make silly mistakes that cost me a correct answer.

Can you put up a diagram just so I can see how you drew your constraints, and what inferences you made before going to the questions.
Thx, KT

[bbirdwell]

No problem! Here ya go.

See attached diagram below.

The game seems tough at first due to the uncertainty of how many Fs and Gs and Os you must use (and 8s 9s and 10s for that matter), but there are some truly killer inferences you can make up front.

We call this a 3-D numbered ordering game. Two horizontal rows to keep track of the two groups of elements: people and centuries.



Hope that helps!
^b

[daniel520justin]

Thanks for the sharing...I just cannot understand how come the last condition - the site visited third dates from a more recent century than does either the site visited firt or that visited fourth - means V3 is later than both V1 and V4. I think, either...or...has three possibilities: 1, V3 is later than V1 but not V4, 2, V3 is later than V4 but not V1, and 3, V3 is later than both V1 and V4...Simply, you just cannot be so sure that V3 is later than both V1 and V4...Could you please explain a little more about this? I appreciate anyone who could help!!!

[bbirdwell]

Yeah, this is a really tricky one. It's an awkward construction that I haven't seen anywhere else on any test.

The thing is, if you work it the way you've interpreted it, you cannot answer #14. So at that point you'd have to re-think it.

I think the key is the placement of the word "does."

Consider this:

1) John plays guitar better than either Lee or Tom.

2) John plays guitar better than does either Lee or Tom.

3) Either John plays guitar better than Lee, or else he plays guitar better than Tom.

Pay attention to the subtle difference in the language. These are different clues, though on the LSAT I would expect 1) to have some extra words at the end (see below).

For 1), we would expect two possibilities: J--L or J--T, but not both. When this is the case, it's an LSAT convention to explicitly state "either X or Y but not both."

For 2), the reverse is true. The "either/or" in this case may be interpreted "both" or "and." J--L and J--T.

3) is a clear case of J--L or J--T.

Does that help?

[seven7lx]

Very good explanation, bbirdwell.

So for: John plays guitar either better than Lee or better than Tom. Does it mean J---L, or J---T, or both? If not, what's the case when "either A or B" means A or B or both A and B?

Another question, I thought the site visited first must be from 8th, coz all other sites can't be from 8th. But apparently, this is not case. Site first can be 8th or 9th. Is it because it didn't say each *exactly* dates from 8, 9 or 10?

Please help! Thanks.

[bbirdwell]

For your first question, the answer is to remove the "both" part.
Either/or means either/or, and not both.

So if J comes either before M or after K, then you have
J--M or K--J. Typically, the test will say "either/or...but not both."

For your second question, it need not say "exactly," but it would have to say something like "each of the centuries occurs at least once," or something like that. This is a critical question to ask yourself on all assignment games of 3D ordering games: "MUST every element be used?"

[theonlyrij]

Can someone tell me when the constraint says "exactly one of the sites was discovered by Gallagher, and it date from the tenth century" that means that out of the 5 sites there can only be one G right?

If that is so, then in the diagram, shouldn't site 3 be G and site 5 be F and not F/G?

Thank!

[timmydoeslsat]

It can still be true that another archaeologist discovers a 10th century site.

Do not reverse the logic.

If G ---> 10th

10th ---> ? It could be G, but does not have to be.

However, if at any point in the game, you have only one tenth century site, it must be Gallagher's as every person must discover a site.

[bbirdwell]

It can still be true that another archaeologist discovers a 10th century site.

Do not reverse the logic.

If G ---> 10th

10th ---> ? It could be G, but does not have to be.

However, if at any point in the game, you have only one tenth century site, it must be Gallagher's as every person must discover a site.

exactly!

[allisonviramontes]

I was just wondering how we know slot 4 has to F. Why can it not be G?

thank you in advance!!

[timmydoeslsat]

Let us talk about what we know about G from the rules.

It is used one time and one time only.

That lets us infer that the maximum number of times that another variable can go is theoretically 4 because there are 5 slots and one, and only one, is discovered by G.

If G discovers a site, according to the third rule, it is from the 10th century.

Notice the first rule states that the second site is from the ninth century, we will put that in the diagram. This is an advanced linear game.

Because of the second site being from the ninth century, we can infer that G cannot discover that site. If it is G it must be 10.

That means that either F or O will discover that site.

Next rule states that O will not discover the site visited fourth or fifth.

So that means that F or G will discover that site.

The site visited third dates from a more recent century than the first or fourth.

We now know that the fourth site cannot be a 10th century because then there is no way that the third site would be of a more recent century. That now precludes G from going into slot 4. This only leaves one variable left since O is barred from that site because of the second rule and G with the most recent rule.

Now we know that this particular site of 4 must either be an 8 or a 9 for its century.

However, since we know from the rules that 8th---> O

And we do not have O in four, we can use the contrapositive to trigger a ~ 8. Thus, we know that four must be a 9, which means that slot three must be 10 to retain its status as it being of a more recent century. As for the site being first, we know that the third is from a more recent one, thus is cannot be 10. Thus is cannot be G. So slot one will be an 8/9 century and a F/O architect.

[tsj215]

where is the diagram attached?

Also im confused as to why F is in slot 1 and not O

Since slot 1 and 4 has to be less than slot 3 (G=10) and O is forbidden in slot 4/5. Wouldnt slot 1 have to be O=8?

[ManhattanPrepLSAT1]

Hey tsj215, I reposted the diagram for this one up above in Brian's original post.

To your question more specifically, remember that 8 implies O, but O does not imply 8. Also, G implies 10, but 10 does not imply G. So while G could discover the 3rd site, G could also discover the 5th site.

Also, It's not the case that every archeologist necessarily discovers at least one site. It's possible that the sites are discovered by: F F G F F, in that order--though there are other possibilities as well.

It is true that if a site dates from the 8th century, it will be the first site, but it doesn't have to be. The first site could also date from the 9th century.

Hope that helps!