This is an explanation of the first logic game from Section II of LSAT Preptest 38, the October 2002 LSAT.
Eight clowns got out of a car one at a time in a circus show (Q, R, S, T, V, W, Y, Z). The clowns get out of the car and into the center ring. The rules determine what orders the clowns can get out in.
Game Setup
This is a sequencing game. They aren’t too common, but they are very standard. If you know one you can easily solve any of them. The trick is to turn all the rules into one large diagram that tells you how everything is ordered.
(on recent LSATs, the LSAC has thrown in conditional rules, because people were getting too good at pure sequencing games)
The diagram I’m going to show you is simple. The ordering goes from left to right for those things that are connected by lines. If a letter has a line to the right of it that connects it with another letter than the 2nd letter is later. If 2 variables have no lines between them then we have no idea which one goes 1st.
This will be easier with pictures so let’s diagram the first rule:
You can see that V goes before both Y and Q, because there is a line between V and both of those letters.
There is no relationship between Y and Q because no line directly connects those 2 letters.
Here’s rule 2:
As you can see, we just add new rules on to the diagram.
It’s important to learn how to read these diagrams. There is no relation between Z and Y because there is no line between them. We can only read from left to right.
Here’s rule 3. R is before T and that T is before V:
How To Interpret These Diagrams
Some people understand this type of diagram instantly. But for others it’s not so easy.
If you’re still not sure how this works, put your finger on the R. You can see how R is connected to all the other letters by tracing a line from left to right with your finger.
If you can trace a continuous line from R to another letter without going backwards then R is before that letter.
If you have to go backwards or if there is no line between 2 letters then there is no relationship between the letters.
So R is before T, V, Y, and Q. You have to go backwards to connect R to Z, so there is no relationship between them.
Both R or Z could be 1st. Likewise both Y and Q could be last.
If you’re still not sure how to read the diagram, then go back and read over each individual rule and think about how they fit together.
Apply those rules to this diagram and see how to match everything up. Now let’s add rules 4 and 5. W is after R, and S is after V.
This Diagram Solves Everything
And we’re done. There’s no contrapositive because these rules aren’t conditional statements.
This is just an ordering diagram; it tells us who can go 1st, who can go last and how all variables are related to each other.
Since there is just one diagram it is very important that you understand. Look over the diagram and see who can go 1st and who can go last. R and Z are the only variables that can go 1st because no variables come before them. S, Y, W and Q are the only variables that can come last because no variables come after them.
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