Setup and Rule Diagrams

[Dave Killoran]

This game is also discussed in our Podcast, at the 24:24 mark: LSAT Podcast Episode 37: The November 2019 LSAT Logic Games Section

Setup and Rule Diagram Explanation

This is a Grouping/Linear Combination, Identify the Templates Game

The game scenario establishes that a chef is creating a soup recipe by adding a selection of seven ingredients: G, J, K, O, P, T, and Y. This selection process focuses on Grouping, and the selected ingredients will then be added one at a time, creating a Linear component.

The rules break into two basic groups: the first three rules focus on J, P, and Y, and the last two rules focus on G, K, O, and T. Since the last two rules establish that all four ingredients are selected, you should begin your analysis there.

Rule #4 includes G, K, O, and T in every single recipe, and Rule #5 places the four ingredients in a base sequence. We'll address both the Grouping and Linear aspect up front:

•  G K O T
  In Out
  
  
  
  
  K
  O G
  T
  
  (this diagram is imperfect due to the limitations of the Forum, but the idea should be clear)

The information above provides an excellent foundation for this game, and helpfully addresses 4 of the 7 variables in play. The first three rules then address the remaining three variables:

• Rule #1: This rule states that if J is included, then J must be first or last.
  
  J first/last
  
  Rule #2: This rule adds that if J is included, then Y is not:
  
  J Y
  
  Rule #3: And this rule adds that exactly one of P and Y is included, meaning the other must not be included.

From a Grouping standpoint, the following is known in general:

• G K O T P/Y      Y/P
  In Out
  
  J?

Given that there are only two states for any ingredient in this game—In the recipe or Out of the recipe—and J is so powerful, it makes sense to explore what occurs when J is included and not included:


Template #1: J is selected for the recipe

When J is included, it must be first or last, and Y cannot be an ingredient. Consequently, P must be included as an ingredient:

• J P G K O T       Y
  In Out
  
  
  K
  J/ O G /J
  T
  
  P?

Template #2: J is not selected for the recipe

If J is NOT included, then either P or Y can be included:

• G K O T P/Y      J Y/P
  In Out
  
  
  K
  O G
  T
  
  P/Y?

At this point, you can use the two templates to effectively attack the game, and the questions become relatively easy.

[jailenea]

Would it be acceptable to diagram rule 3 as a conditional or as a biconditional, each of which could be done (and the latter of which is done by you) for rule 2? I had the following:

P --> ~Y
Y --> ~P

and this can be simplified to P:dblline: Y

Is this not the same as saying one of them must be in and one must be out? Well, now that I'm writing this, is making it conditional wrong because it allows for the possibility that both P and Y be out whereas the written rule doesn't allow that to occur?

[Rachael Wilkenfeld]

Exactly jailenea!

You'd need two separate conditional rules

P Y

AND

P Y

Note that they aren't contrapositives of each other. They are different rules that give different information. The first rule states that you can't have P and Y together. The second rule states that you must have either P or Y. Personally, for this kind of game, I typically just like to use the in/out slot to track that sort of rule. However, the conditional would be valid.

Hope that helps!