Diagramming Solutions for PrepTest 77

Utilizing methods taught in The LSAT Trainer.

Game 1 (Option 1)

Step 1

Per the given scenario, we can write out the six elements to be placed - R, S, T, W, Y, and Z, and we can lay out the six assignments - 9, 10, 11, 2, 3, and 4, separated out into morning and afternoon.

Step 2

Per the first and fourth rules, we can notate that R and Z must go in the morning, with R before Z.

Step 3

Per the second rule, we can notate that Y must immediately follow W.

Step 4

Per the third rule, we can notate that T must perform in the afternoon.

Step 5

We can mark that S is not restricted by any of the given rules.

Game 1 (Option 2)

Step 1

Step 2

Per the first and fourth rules, we know that R and Z must go in the morning, with R before Z. We can create three frames around the different ways that this can happen: with R in 1 and Z in 2, with R in 1 and Z in 3, and with R in 2 and Z in 3.

Step 3

Per the third rule, in all frames, we can notate that T must go in the afternoon.

Step 4

For frame 1, per the second rule, we can notate that Y must immediately follow W.

Step 5

For frame 2, the WY pairing can only go in the afternoon, and we can notate that. That leaves S as our only option for the open 10 am slot.

Step 6

For frame 3, the WY pairing can only go in the afternoon, and we can notate that. That leaves S as our only option for the open 9 am slot.

Game 2

Step 1

Per the given scenario we can write out the eight elements to be placed - L, M, N, O, P, R, S, and V - and we can lay out the six positions to be assigned, in order, as well as two positions for those not assigned.

Step 2

Per the first rule, we can notate that if L is in, M is out, as well as the contrapositive. We can infer from this rule that either L or M must be out.

Step 3

We can create a note that for all remaining rules, our notations only apply if that element is displayed.

Step 4

Per the second rule, we can notate that P can only be displayed if next to both O and S.

Step 5

Per the third rule, we can notate that R can only be displayed in 1 or 6.

Step 6

Per the fourth rule, we can notate that S cannot be displayed in 2 or 4.

Step 7

Per the fifth rule, we can notate that N can only be displaced in 5.

Game 3 (Option 1)

Step 1

Per the given scenario, we can write out the order of preferences for each of the four employees - J, L, P, and T.

* This is a very unusual game, and at this point there is nothing else to notate (the three rules give us information that does not need to be written out, though it certainly can be if you’d like). However, it is very helpful to run through some mental exercises to help conceptualize the game a bit better. A few questions we can ask ourselves, and think about, include:

“Can everyone get their first choice?”

“Can everyone get their first or second choice?”

“Can everyone either get their first, second, or third choice?”

“What’s the earliest or latest that W, X, Y, and Z can go?

Game 3 (Option 2)

Step 1

Create four frames, one each for if J, L, P, or T get the first selection, and assign them each their first preference.

Step 2

For each frame, write out the remaining elements to be assigned, along with their order of preferences (minus the element already assigned).

Step 3

In the frame in which J selects first, notice that no matter who else selects when, office W will be picked last, and X or Z will be picked second or third (in either order). We can fill in the positions with these inferences.

Step 4

In the frame in which L selects first, notice that no matter who else selects when, office Y will be selected second, Z third, and W fourth. We can fill in the positions with those inferences.

Step 5

In the frame in which P selects first, notice that no matter who else selects when, office X will be selected second, Z third, and W fourth. We can fill in the positions with those inferences.

Step 6

For the final frame, there are a variety of ways in which the elements can fill the positions, so we can keep those slots open.

Game 4

Step 1

Per the given scenario, we can write out the five elements to be placed - H, J, K, M, and N - and we can lay out the nine positions to be assigned - three each in groups X, Y, and Z, with each group organized per subset assignments - leader (L), secretary (S), and treasurer (T).

Step 2

Per the first rule, we can notate that N must always be assigned as an L.

Step 3

Per the second rule, we can notate that M can only be assigned once.

Step 4

Per the fourth rule, we can notate that J is assigned to group Y as the secretary (S), and that J can’t be in groups X or Z. We can also notate that this means we have just 1 J.

Step 5

Per the third rule, we can notate that K must assigned as either T or L in group Y, and that K cannot be assigned to Z.

Step 6

Since both J and K cannot be assigned to Z, we can infer that the remaining three elements, N, M, and H, must be, with N taking the leadership (L) position.

Step 7

Per the second rule, we can infer that M is now not assigned to groups X and Y.

Step 8

Since both J and M cannot be assigned to group X, we can infer that N, H, and K must be, with N taking the leadership (L) position.

Step 9

We can note that H is not directly restricted by any of the given rules.

More Information About The Trainer Logic Games Diagrams

These pages offer diagramming suggestions for every game that has appeared in every Logic Games section from PrepTests 52 through 81. Please keep in mind that there are many different ways to effectively diagram Logic Games, and it’s often a very subjective decision as to which inferences to notate, when to split diagrams, and so on.

One significant advantage of the Trainer diagramming methods is that they provide a universal diagramming system that you can use for any game that appears in the section. This is in contrast to most other LSAT learning systems, which separate games out into distinct categories, each with its own, and often conflicting, notational system.

General Suggestions on How to Diagram Logic Games

Always read through the scenario and rules completely, and pause to mentally consider and visualize the game, before setting pencil to paper.
Think of all games in terms of elements to place and positions to place them into. Nearly every game places these positions into an order, into groups, or both.
Whenever you find it useful, feel free to deal with the rules in an order that makes it most convenient for you to draw an effective diagram.
Always be on the lookout for inferences—things that you can figure out by bringing information, such as rules, together. The purpose of your diagram is to, in fact, help you uncover inferences correctly, and these inferences (more so than the rules as they are given) are what determine right and wrong for the vast majority of problems.
Look for opportunities to split up your game board into multiple frames - which are a set of diagrams that collectively represent all of the possibilities of a game. Most commonly, we can create frames around a very limited set of options for how to fill a certain position or positions (“either F or K must be third,” for example) or where to place an element or elements (“K must go first or last,” for example).
Whenever you have trouble notating a rule clearly, don’t be afraid to write it out or provide as much detail as you feel necessary. Better to be safe than overly clever.
When you are done with your diagram, evaluate your notations carefully and check them back against the scenario and rules as written. Make sure that you understand what your notations mean, and that they represent the given information correctly.

Table of Commonly Used Notations

Here is a downloadable and printable infographic that includes the symbols and notations that we will most commonly utilize to set up games. Please click to open full screen.

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