The final question of a game sometimes asks you to substitute a rule. Many people find these questions very difficult, but they don’t have to be. You should ask yourself what the main effect of the rule is.

If J is in, K is in. That forces N out.

If N is in, K is out. That forces J out.

So J and N can never go together, because of the combination of the first and second rules. And if J is in, and N is out, then K must be in, because we always need one of either N or K (the first rule).

So the right answer has to force N out if J is in, and force J out if N is in. Any secondary effect of a rule is almost the only way the LSAT can make a rule substitution answer work.

Answer choice **D** is **CORRECT.** It captures all of this information. If J being in causes N to be out, then K to has to be in, thanks to the first rule. Everyone works out the same.

**A** gets the second rule backwards, and so it has a different effect.

**B** has a different effect as well. Previously, it was possible to have K, O and L all in together. Now this can’t happen. And this answer also ignores the main effect of the second rule: now J no longer forces K in.

**C** is way off base. There was no such relation between O and K in the original setup, and this new rule leave J with no effect on K.

**E** contradicts the old setup. The original rules combine to the effect that if N is in, O and L are in. See the setup for more detail on this point.

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alia says

I was so confused by this question but by looking at the main effect of the rule (as described above) made it seem so simple, thank you so much for the explanation!