Setup and Rule Diagrams

[Dave Killoran]

Setup and Rule Diagram Explanation

This is a Grouping/Linear Combination: Defined-Fixed, Balanced game.

The game scenario establishes the following initial setup:

PT52-Sept2007_LGE-G3_srd1.png

The “1,” “2,” and “3” in the base represents the three days. The “1st” and “2nd” next to each row represent the first and second conference scheduled for each day.

Let us examine the rules in detail.

Rule #1

This rule stipulates that there is one short seminar and one long seminar given each day. Effectively, this creates a series of vertical not-blocks indicating that GO, GP, OP, HN, HT, and NT cannot be given on the same day. However, writing out all six blocks is time-consuming, and thus a more concise representation is:

PT52-Sept2007_LGE-G3_srd2.png

Effectively, this rule separates GOP and HNT into horizontal blocks (in terms of space occupation); but, because of the 1st/2nd scheduling aspect, the variables can move between the first row and the second row.

Rule #2

The second rule is sequential:

PT52-Sept2007_LGE-G3_srd3.png

This rule can be easily misinterpreted because it may appear that T must be scheduled for the third day. Although G and O—both short seminars—must be given before T, it is possible for T to be given 2nd on the second day (G or O would be given 1st that day). However, it can be determined that T cannot be given on the first day or as the 1st seminar of the second day, and that G and O cannot be given as the last seminar of the conference:

PT52-Sept2007_LGE-G3_srd4.png

Rule #3

The third rule is also sequential:

PT52-Sept2007_LGE-G3_srd5.png

Thus, N cannot be the 1st seminar on the first day, and P cannot be the 2nd seminar on the third day.

Consequently, the three Not Laws on the 2nd seminar on the third day (G, O, P) leave only H, N, to T—all long seminars—to be scheduled in that slot. Thus, since a long seminar must be scheduled as the 2nd seminar on the third day, a short seminar must be scheduled as the 1st seminar on the third day:

PT52-Sept2007_LGE-G3_srd6.png

In addition, P cannot be the 2nd seminar on the second day as that would force N into the third day, as well as one of the remaining long sessions, G or O. But the long session on the third day would also have to precede T, forcing three seminars (N, G/O, T) into only two sessions.

With the P Not Law added, and H identified as a random, the final setup for the game is as follows:

PT52-Sept2007_LGE-G3_srd7.png

[dustin.lm]

While taking the Sept 07' LSAT I ran across a Question which had 1 "floater" or "random" variable and illustrates a couple questions I had with Logic games.

The problem went like this:

[PrepTest 52, September 2007 LSAT, Logic Game #3 - text removed due to LSAC copyright restrictions]

First, I can see, from your point on "randoms," that 'H' is one. What is the best way to capitalize on this floater when attacking the questions in the passage? Most of the time I am able to quickly set-up diagram rules and make basic inferences but I guess I got bogged down on this problem and after reviewing it several times I did pretty well but it appeared to me that my diagrams were lacking because of the scarcity of rules, seemed like I wasn't utilizing the random variable because of the scarcity of rules.
On another note, there is no mention of 'AM' or 'PM' in the question, is that something I need to assume or does daily order not matter here?
My chart looks like this:

LS: __ __ __
SS: __ __ __


Is that an okay set-up?

And going forward, if I run across a question on the exam which has daily pairings can I be expected to assume that the grouping to be 'AM' and 'PM' as to distinguish order of the grouping if order for a given day is not specified?
Hope my first question isn't too ambiguous. Thanks David!

Dustin.

[Dave Killoran]

Hi Dustin,

Thanks for the question. Ok, there are a few points to make here. First, they play a bit of trick here, and instead of using AM/PM, they say that, "two of the seminars will be given consecutively," and then later in the questions they reference the slots in the following manner: "Which one of the following CANNOT be the second seminar given on the second day of the sales training conference?" So, they are constantly referencing the order of seminars each day, and to mark this order we can list them as "1st" and "2nd":


2nd:

1st:
1 2 3


This decision will create benefits when we look at some of the rules, such as second and third rules. For example, we can infer that neither T nor N can be the 1st seminar on the first day, or that none of G, O, or P can be the 2nd seminar on the third day. And, continuing on, those Not Laws on the 2nd seminar on the third day are interesting because all three are short seminars, meaning that the 2nd seminar on the third day must be one of the long seminars: H, N, or T. Consequently, from the first rule, that the 1st seminar on the third day must be G, O, or P. In other words, noting the order of the seminars each day unlocks some key insights into the game (I covered a few above, not all of them). I have a feeling that when you change your setup to reflect the above, it will start to fill in a lot more, and that will give you a better handle on the game.

The second interesting point here involves H. While H isn't mentioned by name in any of the rules, it still isn't a random. H is a part of a class of variables in this game--long seminars--that is mentioned in the first rule. Thus, from the first rule, there are actually three relationships that involve H: the not-blocks of HG, HO, and HP. Those rules definitely play a role in the game

One of the things about true randoms in a setup is that they are often weak. Real randoms don't affect other variables, and aside from simply taking up space (Which does have its effects), they don't immediately affect other variables. In maximum questions this means they can be included immediately, but in a setup they are usually the last variables to be relied on for creating insight.

Please let me know if that helps. Thanks!

[dustin.lm]

That helps!

Thanks Dave

[ashkan]

Hi there, I'm having some trouble with game 3 from the Sept 2007 exam about the short and long seminars. I'm not too sure if it is my setup that is giving me problems, if I'm missing key inferences, or both (which is probably the case).

My setup is as follows:

___l___, ___l___, ___l___
1-----2-----3----4----5---6
with each of the 3 units representing a day and the line in the middle separating between the first and second seminar of the day ultimately creating 3 days and 6 seminars.

As for the Not Laws, I have Not T in seminars 1, 2 and 3, Not N in seminar 1, and Not G,O,P in seminar 6 (which means a Long seminar must be the second seminar on day 3 and a Short seminar must be first). This is as far as I got and as a result, am having trouble with questions 14-17.

Can anyone share any pointers or help me figure out what it is that I am missing?
Thanks,
Ashkan

[Dave Killoran]

Hi Ashkan,

Thanks for the question. I'll try to help out here, but I'll tell you know that this isn't a setup game where you are missing some key deduction. Regardless, I'll make a few comments and perhaps it will help a little.

First, I really recommend strongly that you don't use a setup that looks like this:


___l___, ___l___, ___l___


That type of setup makes things more difficult in the long run. Instead, set up this game like this:


2nd: ___ ___ ___


1st: ___ ___ ___
1 2 3


Well, that's the best I can make it look with the limited display tools here. But you get the idea This makes the six spots easier to separate, and makes the Not Laws on each more clear.

Second, this game is more about restrictions (meaning Not Laws) than it is about inferring that a certain variable must be in a particular spot. Here's the thing: you got all of the basic inferences in this game. I would be inclined to note on the main setup that the limitations for day 3 result in triple-options for each seminar, however:


2nd: ___ ___ H/N/T


1st: ___ ___ G/O/P
1 2 3


Overall, the setup in this game doesn't contain some magic bullet that makes it all easier. Instead, this is a game with a straightforward setup where you simply have to apply the rules as you work through. That means that the first rule about a long and short seminar each day, and the two sequences created by the rules will dominate in the questions. I think maybe you got thrown off and were thinking you were missing something, and that made the game feel harder than it actually is. For example, look at the explanation for #14:

• If G—a long seminar—is given on the first day, then the other two long seminars—O and P—cannot be given on the first day. This information eliminates answer choices (B) and (C). From the third rule, then, N cannot also be given on the first day. Combined with the existing Not Laws, this results in a situation where N, O, P, and T cannot be given on the first day, leaving only G and H to be given on the first day. This inference eliminates answer choices (A) and (D).
  
  Thus, answer choice (E) is proven correct by process of elimination.

From your description, you had all the information needed to solve this problem, and I'd say the same is true for the remaining questions. If I were you I'd take another look at this game and see if it doesn't turn out to be more doable than it initially appears.

Please let me know what you think. Thanks!

[ashkan]

Hi Dave,

This definitely does help, I guess my set up kind of threw me off.

Thanks for the help!
Ashkan

[lawana]

Hi, I find this game difficult, there are few things that stops me from moving forward.
starting from the first rule, I looked up the explanation in Sage, and what they say about the first rule confuses me even more. then I came here for further explanation on the first rule, and I don't fully get it, though is much clear than Sage.

rule #1 "exactly one short seminar and exactly one long seminar will be given each day"
to me this means: we have 3 days, and each day has two spaces ei: (1)____ ____, (2)____ ___ , (3) ____ ____ exactly one long or short seminar will be given EACH day, ei if short seminar is in day 1 then both spaces of day 1 are filled with short seminar. In other words, I cannot have short and long seminars the same day (ei day 1). Sage says the opposite, they say that you cannot have two SS or LL the same day.
Please help me understand this, thank you.

rules #2 and #3 I got confused because I read the "until", and I automatically thought of the "unless equation", please correct me if I'm wrong. UNLESS EQUATION is ONLY for conditional statements correct? and rule 2 and 3 were NOT conditional statements and therefore the unless equation doesn't apply here. right?

THANK YOU!

[Adam Tyson]

You are definitely misinterpreting that first rule, lawana - the first rule of the game requires that each day has one short AND one long seminar. That's an AND, and it means you have to have one of each. To belabor the obvious for a moment, if you had two short seminars, you would not have exactly one short seminar, because two is not exactly one, it's two.

As to rules 2 and 3, the fact that they include the conditional indicator "until" tells us that they are very definitely conditional rules! Conditional rules are prevalent in logic games, not just in logical reasoning, and in this case you would not be incorrect to diagram those rules conditionally and to at least think about, if not actually diagram, the contrapositives. Rule 2, for example, might look something like this:

T (G&O T)

While this is accurate, it is not the best way to handle these two rules, though, because in this case there is no question that all of the seminars will be included. If there was some chance that T was not included in the game, then the conditionals would be useful, but since we KNOW that T is in it is more efficient to just handle these rules sequentially, like so:

G
+ T
O

P N

So, the language IS conditional, and a conditional approach would be correct, but in this case it's not the best choice.

I hope that clears things up for you! Keep at it!