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- Thu Sep 21, 2017 4:26 pm
#40022
Setup and Rule Diagram Explanation
This is a Pure Sequencing, Identify the Templates game.
Because Pure Sequencing is generally easy to handle for most test takers, this was an excellent way to begin the Logic Games section of the September 2014 LSAT.
The game scenario establishes that five instrumental pieces must be ordered in a sequence. Because there are no ties, this is a Balanced game. The following linear scenario underpins the sequence:
Although Pure Sequencing games involve relationships that are relative and not precisely fixed, a linear diagram can help us represent inferences that could result from the application of the rules.
The first rule establishes the following sequence:
The second rule establishes two possibilities for the way in which we can order R, S, and T:
Take a moment to understand precisely what this rule entails: T must appear either earlier or later than both R and S. In other words, T cannot appear between R and S, and the following two sequences would be impossible:
Similarly, the third rule establishes two possibilities for the sequence of R, T, and W:
As with the previous rule, here W must appear either earlier or later than both R and T. So, we can never place W between R and T, and the following two sequences cannot be true for any solution of the game:
At this point, we would normally attempt to combine the rules in order to produce a sequencing chain. This step is somewhat complicated by the fact that two of the three rules do not mandate a fixed sequence of variables; instead, they only give us optional, alternating sequences. As a result, producing a single sequencing chain would be impossible—a realization that prompted many test-takers to immediately move on to the questions. Unfortunately, their setup would be lacking without a more thorough idea of the relationships that connect the five variables in the game.
The best approach is to link the rules together, even if such linkage would produce multiple sequencing chains. Essentially, this would be a Templates-based approach, because the chains you make will represent an exhaustive range of solutions. The easiest way to begin would be to combine the first two rules as both of them restrict the placement of S, and the first rule is the easiest to work with. When combined, these rules produce the following two sequences:
Now all we need to do is examine the impact of the last rule on each template: W must appear either earlier, or later, than both R and T. In each template, the relationship between T and R is already known, which makes the implication of the last rule easy to see. In Template 1, W must be placed either before T (and therefore before R), or else after R (and therefore after T):
Similarly, in Template 2, W must be placed either before R (and therefore before T), or else after T (and therefore after R):
In determining relationships between variables, do not let physical proximity on the diagram influence your evaluation. For instance, in Templates 2B, V appears to the right of R, but there is no direct relationship between R and V. It is possible, for instance, that in that template V is second and R—third. The key in Pure Sequencing games is to avoid making unwarranted assumptions such as this.
Thus, we arrive at the following final setup for this game:
While a Templates approach requires an initial investment of time and may appear daunting at first, it is ultimately advantageous in this game. First, the game contains seven questions, rather than, say, five. The higher the number of questions, the more benefit you can expect to derive from these templates. Second, consider the alternative: without the four sequencing chains outlined above, your setup would be practically nonexistent. Yes, you can still attack the questions armed with a solid understanding of the rules alone, but this “plug-and-chug” approach would be terribly inefficient and ultimately take much longer.
This is a Pure Sequencing, Identify the Templates game.
Because Pure Sequencing is generally easy to handle for most test takers, this was an excellent way to begin the Logic Games section of the September 2014 LSAT.
The game scenario establishes that five instrumental pieces must be ordered in a sequence. Because there are no ties, this is a Balanced game. The following linear scenario underpins the sequence:
Although Pure Sequencing games involve relationships that are relative and not precisely fixed, a linear diagram can help us represent inferences that could result from the application of the rules.
The first rule establishes the following sequence:
S 
V
The second rule establishes two possibilities for the way in which we can order R, S, and T:
Take a moment to understand precisely what this rule entails: T must appear either earlier or later than both R and S. In other words, T cannot appear between R and S, and the following two sequences would be impossible:
- R T S
S T R
Similarly, the third rule establishes two possibilities for the sequence of R, T, and W:
As with the previous rule, here W must appear either earlier or later than both R and T. So, we can never place W between R and T, and the following two sequences cannot be true for any solution of the game:
- T W R
R W T
At this point, we would normally attempt to combine the rules in order to produce a sequencing chain. This step is somewhat complicated by the fact that two of the three rules do not mandate a fixed sequence of variables; instead, they only give us optional, alternating sequences. As a result, producing a single sequencing chain would be impossible—a realization that prompted many test-takers to immediately move on to the questions. Unfortunately, their setup would be lacking without a more thorough idea of the relationships that connect the five variables in the game.
The best approach is to link the rules together, even if such linkage would produce multiple sequencing chains. Essentially, this would be a Templates-based approach, because the chains you make will represent an exhaustive range of solutions. The easiest way to begin would be to combine the first two rules as both of them restrict the placement of S, and the first rule is the easiest to work with. When combined, these rules produce the following two sequences:
Now all we need to do is examine the impact of the last rule on each template: W must appear either earlier, or later, than both R and T. In each template, the relationship between T and R is already known, which makes the implication of the last rule easy to see. In Template 1, W must be placed either before T (and therefore before R), or else after R (and therefore after T):
Similarly, in Template 2, W must be placed either before R (and therefore before T), or else after T (and therefore after R):
In determining relationships between variables, do not let physical proximity on the diagram influence your evaluation. For instance, in Templates 2B, V appears to the right of R, but there is no direct relationship between R and V. It is possible, for instance, that in that template V is second and R—third. The key in Pure Sequencing games is to avoid making unwarranted assumptions such as this.
Thus, we arrive at the following final setup for this game:
While a Templates approach requires an initial investment of time and may appear daunting at first, it is ultimately advantageous in this game. First, the game contains seven questions, rather than, say, five. The higher the number of questions, the more benefit you can expect to derive from these templates. Second, consider the alternative: without the four sequencing chains outlined above, your setup would be practically nonexistent. Yes, you can still attack the questions armed with a solid understanding of the rules alone, but this “plug-and-chug” approach would be terribly inefficient and ultimately take much longer.
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