June 2007 LSAT, Logic Game 4, Question 20

LG Game 4 Question 20 Explanation

This question says center 2 recycles three kinds of material. When that happens, that means center 1 recycles the same three kinds of material (rule 2).

That means that plastic is in center 3, because plastic can only go once. And therefore glass is in centers 1 and 2 (rule 3: PG can’t go together):

That’s enough to solve this question. C is CORRECT.

When you make any deduction on a must be true question, you should always check to see whether it solves the question! There’s no sense doing extra work.