LSAT 69, Game 3, Setup, Juice and Snacks

This is the third logic game from Section II of LSAT 69, the June 2013 LSAT. A company is operating vending machines in four schools: Ferndale, Gladstone, Hafford, and Isley (F, G, H, I). The company has to deliver juice and snacks (J, S) to each of the four schools.

This game is a mix of grouping and linear. More importantly, it’s one of those rare games where you can figure out almost everything before starting.

This game type used to be common, but it’s rare on the modern LSAT. Now, games tend to test your memory of the rules, not your ability to combine rules up front.

However, up-front-deduction games still happen often enough that you should practice them multiple times. Once you get good at making up-front deductions, these are the easiest games on the test.

Base Diagram

First, we’ll set up the game like the first question does:

I’m going to skip the first rule, and draw rules two and three. Always start with rules that are definite:

Next, the fourth rule. The first juice and the final snack are always the same. Here’s a diagram to help you visualize it. The two spots by marked by an X will always be the same variable:

Now, let’s go back to the first rule. F is earlier than H, in the snacks row. That makes snacks pretty restricted. Three rules affect the snacks row.

The final spot is particularly restricted. All three snack rules affect that spot. Who can go last?

• Not G, G goes third.
• Not F. F has to go before H.

So only H and I can go last in the snack row. Whenever a game offers only two possibilities, you should make two diagrams.

First Scenario – Isley First And Last

Let’s start with I:

F and H are the only snacks left. Rule 1 says that in snacks, F has to go before H:

Finally, the last juice can only be F or H. I is already first, and G can’t be the last juice (rule 2):

It may seem obvious that only F/H can go last, but it’s always worth drawing every deduction.

Second Scenario – H First And Last

Next, let’s do the diagram where H is the last snack:

F and I are the other two snacks. They can go in either order:

The final juice is I or F. That’s because G can’t be last (rule 4) and H is first.

So there are only two diagrams. They cover all the rules. This makes the game very easy to solve.

With each diagram, you just have to remember which juices are left to place: G, and one of the two juices from the final space.

How To Make Deductions

I want to talk about how to make these diagrams. It’s easier than it looks. I just added rules one by one.

Once I added a rule, I stopped to think about what spot was the most restricted.

• Were there any spots where only two variables could go?
• If only two variables were left, did I know their order?

Once you make a deduction, stop and think again. Are there any new spots that are restricted, or where there only two variables left to place?

Each deduction you make further restricts the game. Re-examine the game whenever you make a deduction.

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