Using contapositives in a game with negative grouping rules

[Bensquick]

Hi there,

First of all I wanted to say thanks for providing such a great resource!! The books and this forum have undoubtedly prepared me well for my first LSAT next week!

I've got a pretty general question about the use of contrapositives in grouping games where the rules are mostly negative (e.g. A and B cannot be selected together).

On page 285 of the latest LGB it mentions the equal importance of negative grouping rules. With the goal of any logic game being to make inferences, if I was faced with a game that contained many negative rules and a couple of positive ones, would it be worth writing out the contrapositives to the positive rules in the hope of making connections faster?

Obviously it depends on the exact game, but if we were to generalise, would it be something worth doing?

Cheers!
Ben

[AthenaDalton]

Hi Ben,

This is a very game-specific question!

My advice is to quickly (and neatly!) sketch out the contrapositives if you get the sense that some of the rules will fit together into inference chains. Some games just have a series of rules that don't fit together, like A B; C D, and E F. In such a case, you wouldn't get very far in sketching out contrapositives.

If, however, there is potential for letters to link up, it could be worthwhile to sketch out some relationships. Here's an example of rules that would link together: A B; B C; B E. Since B appears in multiple rules, you can make powerful inferences about how several variables interact at once.

I hope that gives you an idea of where to start. In any case, attack each game with confidence and don't get bogged down on any one question, setup, or game. Best of luck with the test next week!

Athena Dalton