LSAT · Logic Games58 flashcards

Must be true questions in LG

58 flashcards covering Must be true questions in LG for the LSAT Logic Games section.

In Logic Games on the LSAT, "must be true" questions ask you to identify statements that are inevitably correct based on the game's rules and setup. These questions involve analyzing a scenario, like arranging people or objects under specific constraints, and then determining what must always hold true no matter how the elements are arranged. This type of question tests your ability to make solid deductions from the given information, helping you build critical reasoning skills essential for legal analysis.

On the LSAT, "must be true" questions appear in the Logic Games section, often as part of a set where you must evaluate answer choices against your diagram. Common traps include selecting options that could be true but aren't guaranteed, or overlooking interactions between rules. Focus on thoroughly mapping out implications and testing for absolute certainties rather than possibilities. Always double-check your work against the game's constraints to avoid errors. A key tip: Eliminate answers that introduce any "could be" scenarios.

Terms (58)

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    Must Be True Question

    A question in Logic Games that asks for a statement that is always true based on the game's rules and setup, requiring you to identify necessary inferences rather than possibilities.

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    Necessary Inference

    An inference that must follow from the rules and entities in a Logic Game, meaning it is impossible for the game to be set up without this condition being met.

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    Difference from Could Be True

    Unlike Could Be True questions, which seek statements that are possible under the rules, Must Be True questions require statements that are guaranteed in every possible scenario of the game.

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    Using Game Rules

    In Must Be True questions, you apply the game's rules to deduce what must always hold, often by testing scenarios or combining rules to eliminate possibilities.

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    Global Inferences

    Inferences that apply to the entire game board, such as a rule that affects all entities, which must be considered for Must Be True questions to ensure they hold universally.

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    Local Inferences

    Inferences specific to certain parts of the game, like a subset of entities, which may still be necessary and thus relevant for Must Be True questions in those contexts.

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    Contrapositives in Inferences

    The contrapositive of a rule can help identify what must be true by revealing equivalent logical necessities, such as if A implies B, then not B implies not A.

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    Combining Rules

    To answer Must Be True questions, you often need to integrate multiple rules to find overlapping constraints that force certain outcomes.

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    Eliminating Possibilities

    A key strategy for Must Be True questions is to check if a statement holds in all possible diagrams; if it doesn't, it's not must be true.

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    Fixed Positions

    In some games, certain entities must occupy specific spots due to rules, making statements about those positions must be true.

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    Limited Options

    When a game has few possible arrangements, Must Be True questions can be answered by verifying what is common across all those arrangements.

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    Avoiding Assumptions

    For Must Be True questions, you must base inferences solely on given rules and not introduce external assumptions that aren't supported.

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    Common Wrong Answers

    Answers that could be true but aren't guaranteed, such as those based on one scenario only, are traps in Must Be True questions.

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    Testing Answer Choices

    A method for Must Be True questions where you plug in each answer to see if it holds in every possible game setup.

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    Diagramming for Inferences

    Creating complete diagrams of the game helps reveal what must be true by showing patterns that repeat across all valid setups.

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    Negative Rules

    Rules that prohibit certain arrangements can lead to must-be-true statements about what is therefore required elsewhere in the game.

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    Conditional Rules

    In Must Be True questions, conditional rules like 'if A, then B' imply that without B, A cannot happen, aiding in necessary deductions.

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    Entity Restrictions

    Rules limiting where or with whom entities can be placed often result in must-be-true facts about their possible locations.

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    Maximum and Minimum

    Statements about the maximum or minimum number of entities in certain positions can be must be true if derived from the rules.

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    Chain of Implications

    A series of conditional rules can create a chain that forces certain outcomes, which must be true in the game.

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    Floating Rules

    Rules that don't fix entities but impose conditions can still lead to must-be-true inferences when combined with other constraints.

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    Subgame Analysis

    Breaking down a game into subgames or scenarios helps identify what must hold across all, crucial for Must Be True questions.

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    Irrelevant Information

    In Must Be True questions, disregarding irrelevant details ensures you focus only on what the rules enforce.

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    Double-Checking Diagrams

    Verifying that your diagrams cover all possibilities prevents missing what must be true in overlooked scenarios.

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    Must Be True vs. Could Be False

    A statement must be true if it cannot be false in any valid game setup, helping to distinguish correct answers.

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    Ordering Constraints

    Rules about order, like sequencing, often make certain sequences must be true due to positional restrictions.

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    Grouping Constraints

    In grouping games, rules about group membership can force certain entities to always be together or apart.

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    Hybrid Games

    For games combining elements, Must Be True questions require considering interactions between different game types.

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    Time-Saving Shortcuts

    Advanced technique for Must Be True questions: look for rules that directly imply the answer without full diagramming.

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    Contradiction Testing

    To confirm a must-be-true statement, assume it's false and see if that leads to a contradiction with the rules.

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    Partial Blocks

    In games with partial blocks or pre-filled spots, what must follow from those can be a must-be-true inference.

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    Numerical Limits

    Rules setting numerical caps or floors can make statements about quantities must be true.

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    Mutual Exclusivity

    When rules make certain pairings impossible, the absence of those pairings becomes a must-be-true fact.

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    Cyclic Dependencies

    In complex games, cyclic rule dependencies can reveal what must always occur due to the loop of conditions.

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    Advanced Inference Chains

    Building longer chains of inferences allows identifying subtle must-be-true elements in intricate games.

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    Scenario-Specific Musts

    Even in games with multiple scenarios, elements common to all scenarios are what must be true.

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    Rule Interactions

    How rules interact, such as one rule negating another's possibility, can pinpoint must-be-true outcomes.

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    Elimination of Variables

    Rules that eliminate certain variables from positions make statements about those eliminations must be true.

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    Forced Choices

    When a rule forces a choice in one area, it can necessitate outcomes in others, leading to must-be-true statements.

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    Overlapping Constraints

    Where multiple rules overlap to restrict options, the resulting necessities are must-be-true.

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    Base Case Analysis

    Analyzing the base or simplest case of a game can reveal what must hold in more complex variations.

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    Counterexample Search

    For Must Be True questions, if no counterexample exists where the statement is false, it must be true.

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    Logical Equivalents

    Recognizing logical equivalents of rules helps in deducing what must be true without rephrasing.

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    Distribution Rules

    Rules about how entities are distributed can force certain distributions to be must be true.

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    Sequence Integrity

    In sequencing games, maintaining sequence integrity ensures certain orders must occur.

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    Exclusion Principles

    Principles that exclude entities from categories make those exclusions must be true.

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    Dependency Graphs

    Mentally mapping dependencies between rules can highlight what must follow in a chain.

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    Minimal Configurations

    Considering the minimal setups that satisfy rules reveals what is invariably present.

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    Maximally Constrained

    In highly constrained games, almost everything might be must be true, requiring precise identification.

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    Trap of Probability

    A common trap is confusing what is likely with what must be true, so focus on certainty.

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    Answer Choice Phrasing

    Must Be True answers are phrased absolutely, without words like 'sometimes' or 'possibly'.

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    Worked Example: Simple Ordering

    In a game where A must be before B, it must be true that A is not after B, as derived from the rule.

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    Worked Example: Grouping

    If a rule states that if X is in group 1, Y must be too, then in scenarios with X in group 1, Y's inclusion is must be true.

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    Advanced: Multi-Layer Inferences

    In complex games, multi-layer inferences from combined rules reveal deeper must-be-true elements.

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    Strategy: Prioritize Core Rules

    For efficiency in Must Be True questions, start with the most restrictive rules to build necessary inferences.

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    Trap: Overgeneralization

    A pitfall is assuming a pattern from one scenario applies universally when it doesn't, leading to incorrect must-be-true claims.

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    Example: Fixed Entity

    If a rule places entity Z in slot 3, it must be true that Z is in slot 3 in every valid arrangement.

    In a sequencing game, if Z must be third, then 'Z is not first or second' is must be true.

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    Example: Mutual Prohibition

    If two entities cannot be together, it must be true that they are separated in all setups.

    In a grouping game, if A and B can't be in the same group, then 'A and B are never together' is must be true.