This is an explanation of the fourth logic game from Section II of LSAT Preptest 38, the October 2002 LSAT.
Five musical pieces: Nexus, Onyx, Synchrony, Tailwind, and Virtual (N, O, S, T, V) will be performed successively by a group of musicians. Two instruments will be used for each piece: Nexus with fiddle and lute (F, L), Onyx with harp and mandolin (H, M), Synchrony with guitar and harp (G, H), Tailwind with fiddle and guitar (F, G), and Virtual with lute and mandolin (L, M). You must determine the possible order of the pieces and instruments being shared between them.
This game looks superficially linear, but it’s really more of a grouping game. The most important element is mastery of the rules; we’re not able to deduce much during the setup.
Each piece is performed by two instruments. It’s important to write this down somewhere you’ll be able to see it clearly and refer back to it.
We only have two rules:
- N or T goes second
- Each piece must share an instrument with the piece before or after it.
The second rule does not mean that a piece has to share instruments with both of the pieces beside it: one is enough.
That’s a common mistake on this game, so I’ll say it again: A piece only has to be linked with either the piece before it or the piece behind it.
A piece does not have to be linked to both the pieces before and behind it.
I found it useful to write down the pieces that could go beside each piece. For instance: N plays F or L. T has F and V has L, so N needs one of either T or V beside it.
Keep the above chart somewhere you can refer to it easily. The game depends on quick access to this information.
Finally, here’s how we can layout the five pieces.
The lines underneath show where we must have links. The piece is spot 1 can only be linked to the piece in spot 2. There doesn’t have to be a link between 2 and 3, because the piece in spot 3 could be linked to the piece in spot 4 (while spot 2 is linked to spot 1.)
Therefore, when N is in 2, either T or V must be in 1. They’re the only ones who could allow a link between 1 and 2. When T is in 2, one of N or S must be in 1.
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