LSAT 70, Logic Game 2, Question 9

This is a common question type on in-out games. It asks which two people can’t go together.

You’re looking for the following relationship:

1. The variable on the left is in positive form. i.e. “S”
2. The variable on the right is in negative form i.e. “M”
3. Example: S ➞ M, M ➞ S

In other words, one variable being in forces the second variable out. This method works whether you look at the main diagram or the contrapositive. Pick a pair of variables from an answer and look for the left most variable on either of the diagrams. Then see if it matches the form I described above.

A is wrong. There are no arrows connecting M and T.

B is wrong. There are no arrows connecting O and Y.

C is wrong. Z has no rules, it can never force another variable out.

D is CORRECT. If S is in, W is out:

(T is in too of course. I’ve only circled the variables leading from S to W in order to clarify the relationship you’re looking for on this question.)

E is wrong. If W is in, Y is in. Clearly, those two can be together.

---