June 07 LSAT, S1, G4 There are exactly three recycling

by **noah** Wed May 13, 2009 2:18 pm

People often freak out about this game, so I figured I'd throw up the solution to this one. To see the diagrams, you'll have to download the doc.

Good luck!

- Noah

This is very similar to the second game. We have three centers (Center 1, Center 2, and Center 3) that each recycle at least two and no more than three of five different types of materials (G, N, P, T, and W). The exact number of materials recycled by each center is unknown.

See the download at the bottom of this post for all diagrams!

Will all the slots be filled? Not necessarily. Each center has the potential to recycle a maximum of three materials. The boxes represent slots that must be filled (each center recycles at least two materials). Will all the letters be used? Yes. The scenario says that "exactly five kinds of materials" are recycled at these three centers. Will some letters be repeated? Well, we have at least six slots that must be filled and only five letters, so we know for sure that there will be at least one repeated letter, if not more.

Setup
Let’s have a look at the constraints. The first constraint says that any center recycling W also recycles N. We saw a constraint like this one in the last game! If we have W, we must also have N.

Notice that we have chosen to represent this constraint vertically to match the vertical columns of our diagram. Pairing two letters together in the same recycling center means putting them in the same vertical column. Thus, we want our notation to reflect this. The second constraint tells us that anything in Center 2 must also be present in Center 1. Make a note on the diagram.

The last constraint tells us that exactly one center recycles P, and that that center does not recycle G. From this constraint, we can infer that center 2 must NOT recycle P! Remember, anything center 2 recycles center 1 must recycle as well. If we put P with center 2, we’d also have to put it with center 1.

Again, notice that we have chosen to represent "no P and G together" vertically rather than horizontally.

The Questions

23. (A)
Question Type: Conditional
The conditional information in this question is that center 1 is the only center to get W. Let’s follow the chain of inferences again!

If 1 is the only center to get W, this means that 2 does not get W. This means that 2 gets exactly two materials, and that 1’s other two materials will match 2’s. Since 1 must also get N (wherever there’s a W there must also be an N).

Center 2 can’t get P, so center 1 can’t get it either in this case. Thus, P goes to 3. If P is in 3, center 3 can’t get G. Thus, center 2 and center 1 get G.

Thus, T must go to center 3.

So, 1 and 2 are completely defined. None of the answers match 1 and 2, so the correct answer must match 3. The only one that could work is (A).

June 07, S1, P23.pdf: (26.39 KiB) Downloaded 402 times