This is an explanation of the fourth logic game from Section III of LSAT Preptest 73, the September 2014 LSAT.
Three floral bouquets are being prepared by a florist, in response to a customer’s order. Each bouquet should include one or more of these kinds of flowers: lilies peonies, roses, snapdragons, and tulips (L, P, R, S, T). You must determine the flower combinations based on the rules.
This is a grouping game, oddly similar to the third game. I drew it vertically, like the first question:
I drew a unique diagram to add the rules to this diagram. When a game presents something you’ve never seen before, you need to innovate. The goal is to make a diagram that’s clear and reminds you of the rule. It doesn’t need to be “correct” (there is no one correct diagram); your innovated diagram just needs to be useful. Here’s what I drew:
This represents the idea that bouquets 2 and 3 need exactly two flowers in common, and bouquets 1 and 3 cannot have any bouquets in common.
In practice, I memorized these two rules. The lines are just a memory aid. If you go into a game like this without memorizing the rules, you’re at a severe disadvantage.
Note: I drew these lines on my main diagram, but I did not draw them on the diagrams I drew beside each question. In these explanations, I’ve kept the lines to the left on most diagrams for clarity. But generally your new diagrams should be simpler than the main diagram.
I’m going to draw rules 4 and 5 before rule 3:
I’ve drawn the contrapositives. On my own game sheet, I did not do this. When you get to an advanced level, you’ll be able to see contrapositives in your head. But until that point, you should draw contrapositives.
Finally, rule three says that bouquet 3 has snapdragons. If we combine this with rule 4, we can say that bouquet 3 cannot have lilies:
I’ve also drawn that bouquet 1 cannot have snapdragons. That’s due to rule 1: bouquets 1 and 3 cannot have any flowers in common.
Those are all the deductions. As with most modern games, the key to success is simply knowing the rules well and applying them when the questions give you new rules.
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