LSAT 70, Logic Game 2, Question 12

This is a slightly unusual question. Normally, when looking for a pair where at least one has to be in, you would look for a pair with the sufficient negated, and the necessary in. E.g. Q ➞ M

But there are no pairs like that in this game. So we’ll have to use a different method to find out what variables must be in.

The fast way to solve this question is to find a couple of working orders. If you find an order that works, you can use it to eliminate wrong answers. Any variables not included in your working order obviously don’t have to be in.

To quickly make two working scenarios, I used the main diagrams. I just started from the left and fulfilled all the sufficient conditions. Like this:

For the first diagram, that gives us WYM in, and OPST out. Add Z in to make four variables in.

Let’s make another working scenario, using the second diagram. If you activate all the sufficient conditions, SPTO are in, and MYW are out.

I also left Z out, because this question is asking who has to be in. Z doesn’t have to be in if we already have four variables in.

So now we have two groups of employees that fulfill all the rules:

WYMZ   and     SPTO

You can use these groups to eliminate answers.

A is wrong. The first group doesn’t include O or S.

C is wrong. The first group doesn’t include P and S.

E is wrong. The second group doesn’t include Y or Z.

Hopefully this method makes sense. I’m attempting to describe the kind of short cut that high scorers use routinely.

Under timed conditions, it took me all of 10 seconds to create those two groups. It takes longer to explain it, because I’m walking you through the steps I went through instantaneously in my head. I recommend practicing this question a few times to get better at quickly creating scenarios to disprove answers.

So now we’ve narrowed things down to B and D. If you use a quick method to eliminate three answers, you can afford to spend more time testing the remaining two. Let’s see if we can create a scenario without OW or without TY.

This scenario eliminates B. MYZT. It obeys all the rules, and doesn’t include O or W. For purposes of illustration, I’ll highlight all the variables I selected across both diagrams. MYTZ are in, POSW are out.

You must read the diagrams left to right. We’ve covered all seven variables across both diagrams, and none of the rules conflict.

D is CORRECT. It’s impossible to construct a correct scenario without either T or Y.

---