Setup and Rule Diagrams

[Dave Killoran]

This game is also discussed in our Podcast, at the 36:54 mark: LSAT Podcast Episode 37: The November 2019 LSAT Logic Games Section

Setup and Rule Diagram Explanation

This is a Grouping: Defined-Fixed, Unbalanced: Underfunded, Identify the Templates, Numerical Distribution Game

This game involves assigning pairs of computer technicians to examine three computers: F, G, and H. The game is complicated because although there are six available spaces, there are only five available technicians. Thus, one of the technicians must be doubled (resulting in a 2-1-1-1-1 distribution), creating the following base setup:

• R S T W X 5
  
  
  
  
  ___ ___ ___
  
  
  ___ ___ ___
  
   F   G       H

The rules are relatively straightforward and can be divided into two groups:

Local Computer rules involved W, W, and X:

• Rule #1: This rule can be drawn as:
  
  SF XG
  
  
  Rule #2: This rule can be drawn as:
  
  WF XH

Because these first two rules are so specific, we will return to them after analyzing the effects of the last two rules.


Block and Not Block rules involving RT and SW:

• Rule #3: This rule creates a vertical WS not-block.
  
    W
  
    S
  
  Rule #4: This rule creates a vertical RT block:
  
  R
  T
  
  Because top or bottom positioning is not a factor in this game, it does not matter if R or T is "on top" of the block.

The last two rules are quite powerful because they address 4 of the 5 variables. The RT block is also limited automatically in position to three separate spots: filling F, filling G, or filling H. Add in that the remaining variable—X—is addressed in the first two rules, and we have a classic situation in which showing the templates would be the best approach. Using the position of the RT block is the best angle of attack:

Template #1: RT block assigned to F

• _R_ ___ ___
  
  
  _T_ ___ ___
  
   F   G       H

Template #2: RT block assigned to G

• ___ _R_ ___
  
  
  ___ _T_ ___
  
   F   G       H

Template #3: RT block assigned to H

• ___ ___ _R_
  
  
  ___ ___ _T_
  
   F   G       H

The immediate impact of using RT as a base for the templates is how it affects the placement of S and W. Because those two technicians cannot be assigned to the same computer, S and W must each be assigned to the other two computers, one for each computer (this would initially appears as a rotating dual-option on the other two computers). However, taking into account the first two rules, we have additional limitations, so let's look at each template as fully realized:


Template #1: RT block assigned to F

This is the most open of the three templates. when S and W are assigned to G and H, there is no rule governing what occurs, and thus X could be assigned to either G or H:

• _R_ _X/_ _/X_
  
  
  _T_ _S/W_ _W/S_
  
   F   G       H

Template #2: RT block assigned to G

In this template, one of S and W must be assigned to F, which will trigger one of the first two rules. Since G is now unavailable with both R and T there, the first rule cannot occur (no room for X), and thus S cannot be assigned to F. Consequently, W must be assigned to F, which triggers the second rule:

• ___ _R_ _X_
  
  
  _W_ _T_ _S_
  
   F   G       H

Template #3: RT block assigned to H

In this template, one of S and W must be assigned to F, which will trigger one of the first two rules. Since H is now unavailable with both R and T there, the second rule cannot occur (no room for X), and thus W cannot be assigned to F. Consequently, S must be assigned to F, which triggers the first rule:

• ___ _X_ _R_
  
  
  _S_ _W_ _T_
  
   F   G       H

With these templates in place, most of the game is locked into place, and your focus should be on the uncertainty in Template #1, and the identity of the variable that is doubled in each template and fills the remaining "open" space.

[mostofthetime]

I have a bone to pick w the phrasing of the fourth rule! I did not interpret it as creating a vertical block. I interpreted it to mean that Ruiz and Tapia examine exactly one computer each. I did not read it as meaning Exactly one computer is examined by both Ruiz and Tapia and it is the same computer. Gah!

Going to podcast now to see if this is addressed. by the gurus.

[mostofthetime]

So I just had another thought on interpreting R4's wording by using other similarly structured sentences in the game...

The problem is in figuring out if Ruiz and Weeks are being referred to as a unit (in other words if 'one' modifies both Ruiz and Tapia separately [as in they both examine exactly one computer but they can be different computers] or if 'one' modifies the UNIT of R & T [ as in they work together for exactly one examination]. In this game it is the latter.

But really, the only guide to interpreting R4 correctly is by reference a similar sentence structure in R3.

R3 says No computer is examined by both Smith and Weeks but it means No ONE computer is examined by both S &W. So R3 also means to take the two technicians as a unit. Not that S & W both individually examine zero computers.

I know it does not mean zero computers because of the setup saying each technician will be assigned to at least one computer.

Very tricky of LSAC to make me think so hard just to get the correct diagram of the block.

[Rachael Wilkenfeld]

Hi mostofthetime,

Let's break down the language of rule 4.

Exactly one computer: That means that there is a single computer that we can point to in this rule.
Is examined: The verb "is" here also indicates we are talking about a single computer.
By both: This means that the single computer is examined by a unit consisting of two people.
R and T: The two people that examine the computer in this rule.

If the rule were telling us that R and T examine one computer each, it would read something like:

R and T each examine one and only one computer or R and T each examine exactly one computer.

Rule 3 is similar---it's stating that there is no single computer that is examined by both R and W.

Sometimes it can help to break down the language in the rules a bit to figure out what exactly the rule is trying to say.

Hope that helps!

[mostofthetime]

Yes, this helps, thanks for breaking it down so clearly.

[RAB]

Quick question regarding R and T. Does the wording that leads to the block rule imply that other than the one computer they both examine together, R does not examine a 2nd computer with another technician (S, W, X) and neither does T (S, W, X)?

[KelseyWoods]

Hi RAB!

No, that rule just says that there is only one computer that both R and T examine together. That doesn't mean that R and T only examine one computer each. Based on that rule, R and T could still examine other computers, they just can't examine any other computers together.

Hope this helps!

Best,
Kelsey

[augl2023]

So, we break it up into different scenarios when a rule like RT are together? and we just show different ways that RT can show up ?

[Dave Killoran]

Hey Aug,

It depends on the game, how it is set up, and the other rules. This approach, known as Identifying the Templates, is triggered by a variety of factors. We cover those factors in our books and courses, as well as on this podcast: https://www.powerscore.com/lsat/podcast/21.

The decision is not always an obvious one, but it can be critical to LG success, so you want to understand why you make these decisions as best as possible. In this game things lined up so taking that approach was the best one. Thanks!