Linear Games Rule Diagramming Drill #8

[LawCraft]

If A sits next to B, then B does not sit next to C.
-PowerScore LSAT Logic Game Bible, (c) 2014

I was only stumped with this question. The Answer Key did not help. I would really appreciate some clarification.

This is how I originally diagrammed the problem:

AB/BA [Block] --> BC/CB [Not Block]

My reasoning:

1) "A sits next to B"

Sufficient Condition. This statement does not indicate any sense of order; it indicates proximity without spaces.

2) "then B does not sit next to C"

Necessary Condition. Similar logic was applied, as stated above.

Would you kindly teach me how to best approach this type of problem? After reading the section on conditional rules, I was quick to identify the necessary and sufficient conditions. However, based on reviewing the answer key, another approach appears to be used.

[Steve Stein]

Hi Lawcraft,

That's a good question, and it brings up the valuable point that there are various ways of looking at some rules.

The way that you diagrammed that rule is completely legitimate, and it would still lead you to the correct answer choices. Let's take a look at the two scenarios that would meet that sufficient condition, A and B next to one another.

(Another way we could read that rule: If A sits on one side of B, then C won't sit on the other side)

AB ABC
BA CBA

The answer key in the Games Bible provides the two specific scenarios prohibited by this rule. What will we never see? We can't have the ABC block, or the CBA block.

I hope that's helpful! Please let me know--thanks!

~Steve