Setup and Rule Diagrams

[Administrator]

Setup and Rule Diagram Explanation

This is a Grouping: Defined-Fixed, Unbalanced: Overloaded game.

The game scenario produces the following initial setup:

PT59_Game_#3_setup_diagram 1.png

While this game may initially appear be to be Linear, (based on the 9 A.M. and 3 P.M. Statistics courses), the course times play no linear role in the game, and the entire goal is to select a group of four compatible courses. Thus, this a Grouping game, with an 8-into-4 scenario where 4 courses must be selected, and 4 courses are unselected.

The first rule establishes that if R is not selected, then J must be selected:


R J


Rules with negative sufficient conditions and positive necessary conditions can be tricky, but this rule indicates that if either R or J are unselected, then the other must be selected. Thus, at least R or J must always appear among Alicia’s course choices (and possibly both):

PT59_Game_#3_setup_diagram 2.png

The second rule establishes a relationship that appears frequently in Logic Games:


M J


This rule can also be diagrammed as:


M J

Combined with the contrapositive of the first rule, these two rules produce the inference that if M is selected, then R is selected:

M R


The third rule is similar to the second rule:

S9 W


This rule also means that when S9 is selected, W is not selected, and thus G must be selected:


S9 G


The fourth rule is a straight positive conditional relationship:


P S9


Combining the third and fourth rules produces the inference that P and W cannot be selected together:

P W


This inference also means that when P is selected, W is not selected, and thus G must be selected:


P G


The fifth rule establishes that G and W cannot be selected together, but that one must be selected. Thus, we can diagram the rule in traditional fashion, and then reserve a space on the diagram for a G/W dual-option:

G W

PT59_Game_#3_setup_diagram 3.png

All of this information can be combined to form the final setup for the game:

PT59_Game_#3_setup_diagram 4.png

[nsd1825]

After a practice test this morning, I was frustrated with this game having to do with Alicia's classes.

I attempted a template solution but it did not provide any help (G/W Rule). I know this is a grouping, unbalanced, overloaded, partially defined game. After this it seems foreign. Trying to work with rules 1 and 2 seems the surest way to start but it has been fruitless so far. Also, the numerical distribution may provide some insights. Smells like an 8 subjects into four classes with statistics being offered twice. But then, Alicia can only take statistics once...

Any assistance on what the process should be here would be helpful. What does the group suggest?

[Nikki Siclunov]

This is not a partially defined game: in fact, the most helpful aspect of this game is the need to select 4 courses out of 7. Yes, Statistics is offered twice, but she cannot take both.

Variables: G J M P R S (9 and 3) W

Rules:

M --> no J --> R

P --> S9 --> no W <--> G

You should see the following inferences:

M --> R
P --> G

Also, based on the first rule, Alicia must take either Russian or Japanese (or both). Based on the last rule, she must take either Geography or World History (but not both). Therefore, the four courses Alicia must take can be listed as follows:

1: R/J (or both)

2: G/W (but not both)

At least one, and at most two, of M, P, and S must be taken.

Regarding templates based on the G/W rule:

If she takes W, she cannot take G, S9, and P. Considering the remaining courses J, M, R, S3, she cannot take both J and M based on the second rule of the game. Consequently, she must take R, S3, and either J or M.

W --> R, S3

I would not do templates: although the selection of W is quite restrictive, the selection of G is not.

[nsd1825]

Thanks for the note and the direction. This provides color to what I am working with this weekend.

Could this be considered a two-value system game? Namely because Alicia is either taking the course or she is not taking the course?

Just curious. :

Nick

[Nikki Siclunov]

Yes, it is a 2-value system game, since (as you said) Alicia is either taking the course or not. But it is the numerical aspect of the game that is the most helpful IMO.

[Annah]

Hi Dave!

Hope you're doing well.

I was attempting Game #3 of PrepTest 59 and the last rule states 'She must take either Geography or World history but cannot take both."
I simply drew this out as G W or inversely as W G
However, as I progressed through the question and began to link the rules together, I could not establish them properly. Apparently I have been misconstruing the meaning of 'either/or'. Does it lead to a further link, one where W is the negative sufficient condition? And does 'cannot take both' always lead to a double not arrow?

When a statement leads to a double not arrow, the SC is normally positive, unless of course the rule states otherwise. In this question, it is not the last rule that by itself yields the negative SC, for if the 'either/or' were not present it would lead to the sufficient condition being positive. The presence of 'either/or' seems to establish a separate rule (which makes it 2 rules in 1) where W and G are represented as negative sufficient conditions.
I am not sure whether this notion is correct and if it is, I am confused as to whether this is always the case with 'either/or' statements or whether this question pertains to something specific I cannot quite grasp.

It would also be helpful if you could explain how this is different from a 'neither/nor' situation.

Thanks!

[Dave Killoran]

Hi Anna,

Good to hear from you. This is a tricky but not uncommon construction, and you got part of it right. A rule such as "She must take either Geography or World history but cannot take both." is really two-rules-in-one, so let's break it down:

• The "first" rule: "She must take either Geography or World history"
  
  In this instance, at least one of G and W is selected, which is diagrammed as:
  
  G W
  W G
  
  Combined, that yields: G W
  
  Thus, one of the two (G or W) is always selected. By itself, this portion of the rule would allow both to be selected. But, the test makers didn't want that to occur, and that's where the second part of the rule comes into play.
  
  
  The "second" rule: "but cannot take both."
  
  In this instance, both of G and W cannot be selected, which is diagrammed as:
  
  G W
  W G
  
  Combined, that yields: G W
  
  Thus, both cannot be selected.

So, what's the bottom line when those two rules are combined? That one and exactly one of G and W is selected, and that the other one is not selected. So, every game solution contains G or W, and either W or G is always among the variables not selected. You got the second part, but the correct diagram for either/or is the first representation. A tricky rule overall!

Please let me know if that helps. Thanks!

[Annah]

Thanks Dave!

That really helps. I just realized you've explained these concepts in detail in the logical reasoning bible as well. I was just having trouble applying them onto this question. But it's clear now.

On a different note, I have been using your logic games classifications in order to sift through games and practice the ones I feel I need to spend more time on. I was wondering if something similar exists for logical reasoning. Especially with regards to conditional reasoning and assumption questions. Please let me know if something along those lines is available.

Thanks!

[Nikki Siclunov]

Hi Anna,

Let me jump in here and add my 2c. The Logical Reasoning Bible, as you are probably aware, does break down the LR questions by type, and also provides in-depth discussion of concepts such as conditional and causal reasoning. As in the Logic Games Bible, each topic or question classification is then followed by a question set.

If you need additional practice, try either (or both) of the Question Type Training volumes we offer:

http://www.powerscore.com/lsat/content_ ... _lrqtt.cfm

http://www.powerscore.com/lsat/content_ ... rqttII.cfm

Each volume contains 1,000 questions classified by type.

Is this what you were looking for? Let me know!

[Annah]

Thanks Nikki!

I'll look into purchasing one of these! They look pretty helpful.