Setup and Rule Diagrams

[Dave Killoran]

Setup and Rule Diagram Explanation

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

This game is Unbalanced because there are nine plumbers, but there are only eight slots (4 teams of 2), so one plumber is always “out” in this game. In this sense, the game has a 2-2-2-2-1 distribution:

J95_Game_#4_setup_diagram 1.png

In this case, we have decided to show the “1 out” space as it is unusual to have 8 variables in and just 1 out, and the nature of the 8—two teams of four—could make it easy to forget that one plumber is always out.

The first two rules are fairly easy to understand. The first rule limits the numerical options for each plumber, and the second rule establishes that at least one plumber on each team must be experienced. The other plumber can be inexperienced or experienced. Thus, we can infer that none of the inexperienced plumbers can be assigned to the same team. This results in a slew of inferences, which we will show shortly.

The third rule is a negative grouping rule (we’ll use arrows instead of vertical not-blocks because so many variables are involved):

• F M, R, V

Under this rule, F has limited options for which plumber he can be paired with.

The fourth rule limits the plumbers that T can be assigned with to G or K:

• T G or K or Out

If T cannot be assigned to G or K, then T must be the one plumber that is not assigned to a team. This rule plays a critical role in the game.

The fifth rule is another negative grouping rule, and prevents J and R from being assigned to the same team:

• J R

From these rules, a number of inferences can be drawn. The first set of inferences involves the fourth rule. Because T, an inexperienced plumber, must be with G or K or out, we also know that none of the other experienced plumbers can team with T:

• F T
  
  J T
  
  M T

Of course, for all three experienced plumbers above, these plumbers already had other negative grouping relationships, which we can add in here:

• F M, R, V, T
  
  J R, T
  
  M F, T

Thus, of the experienced plumbers, only G and K remain, and even they are restricted in that one of them must pair with T if T is on a team.

On the inexperienced side, the inexperienced plumbers each cannot be assigned with each other,

• R S, T, V
  
  S R, T, V
  
  T R, S, V
  
  V R, S, T

Of course, some of these inexperienced plumbers were already limited by other rules, and there are additional negative relationships that can be shown for each:

• R F, J, S, T, V
  
  S R, T, V
  
  T F, J, M, R, S, V
  
  V F, R, S, T

Note that in R’s case, R must be with G or K or M or out.

This results in the final setup for the game:

J95_Game_#4_setup_diagram 2.png

Note that if you have difficulty tracking the plumbers by experience level, simply use I and E subscripts to designate each plumber in the appropriate group.

[kristinaroz93]

game number 6: june 1995 20-24

Is it a good idea to write out all of the double not arrows as shown in the explanation, because it does seem quite time consuming. Is there a better way?

[Nikki Siclunov]

Hi kristinaroz93 ,

This is a game requiring you to put 9 variables into four groups of 2, with one variable out. What drives the rule set is predominantly prohibition rules, i.e. which variables cannot be in the same group as each other. Indeed, 3 of the questions test your understanding of these rules directly. If you find that drawing out each pair of variables separately is too time consuming, you can do this instead:

F M, R, V
J R

Or, you can do what I did when doing this game:

Screen Shot 2015-07-13 at 3.24.59 PM.png

It might look a little messy, but it helps me recognize immediately the subgroup to which each variable belongs (experienced/inexperienced plumbers). This is important, because you need at least one experienced plumber in each group.

Hope this helps a bit!

[kristinaroz93]

This looks like a much better method, thanks so much!

-Kristina

[Blueballoon5%]

For this logical game question, do you recommend writing all the inferences listed in the supplied explanation during the actual test day (if this question was on the exam)? Or are these listed out to simply help us see all the different possibilities?

[Laura Carrier]

Hi Blueballoon,

I would recommend writing out all of the inferences here even under timed conditions, since it would save a lot of time thinking through what is possible on a question-by-question basis. Thinking through the implications of the rules and their interactions at the outset of this game would be very helpful in realizing how limited the possibilities actually are, which in turn would help tremendously with the questions. With the inferences written out, questions 20 and 21 are basically already answered, and the remaining questions become a lot simpler and faster.

I think the time devoted to making a systematic list of inferences such as is shown in the explanation would be more than made up for by the time it would save you in answering the questions. If you think about it, in diagramming the rules you would already have covered variables F, J, and T (except to add to F and J that they can’t be on a team with T), leaving only six more variables to write out. Because it would be too difficult to keep track of all of the numerous restrictions in your head, if you didn't write out the inferences at the outset, you would still end up needing to do most of this work on a piecemeal basis as you answered the questions. But doing it all at once up-front allows you to get a much more thorough understanding of the game.

Most students run into similar questions as they are working with games. At first it can seem quite time-consuming to track so many inferences; but with practice you will become more and more efficient at identifying and recording the inferences. It’s also helpful to re-do the questions in games like this working from a full list of inferences, which will truly give you a sense of how much time can be saved question by question by investing the time to reason things out up-front. There are a lot of factors to be considered when deciding how far to take your diagram, but in games with as many restrictions as this one has, it is usually worthwhile to think them through on paper at the outset.

I hope this helps.
Laura

[Xantippe]

In Lesson 5 HW explanation for Q 24 (5-155) Why must M be assigned to R, and J be assigned to V?

I assigned J to R and M to V and ended up with the correct answer (A) either G or F is assigned to S.

I don't see how I violated the rules in the set up or the conditions in the stimulus. The question in the stimulus says that G cannot be with R, T and V and the rules in the original set up are that M R V cannot be assigned to F. So I understand why K must be assigned to T and why G or F must be assigned to S.


I understand the homework explanation and why the conditions force K to be assigned to T, but, the homework explanation seems to suggest that there is another forced relationship: M is assigned to R and J to be assigned to V. Instead I assigned J to R and M to V. Can both be correct? or am I missing something?

Thanks in advance!

[Dave Killoran]

Hi Xantippe,

Thanks for the question! First, just as a reference, there is a full discussion of this game setup at https://forum.powerscore.com/lsat/viewtopic.php?t=7431, and then a specific discussion of this question at https://forum.powerscore.com/lsat/viewtopic.php?t=16430. The first link in particular will help explain what is happening here

Next, you mentioned that "I assigned J to R and M to V," and the first part there is the problem. In that setup discussion, we discuss how the fifth rule ("Jill cannot be assigned to a team with Roberta") creates a negative grouping rule between J and R, and so no solution with them paired is viable. Thus, J is forced to be with V, and that puts M and R together.

Please let me know if that helps. Thanks!

[admin note- we moved this thread to the first link listed above]

[Xantippe]

I completely missed this rule (I got in the habit of only looking at my diagram and I never write in my books because I want to re-do the questions.

Thank you for the links, very helpful indeed!

[diwil]

Hello,

I do not understand why the inexperienced ones cannot be assigned with each other.

Thanks,

Diana.