Arrangement and Distribution
Arrangement and Distribution problems in LRDI involve organizing people, objects, or events into specific patterns (rows, circles, tables, floors, or categories) based on a given set of conditions. These are logic-intensive sets where clues must be pieced together step by step to arrive at a consistent arrangement.
Common Types of Arrangement and Distribution Problems
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Linear Arrangement
- People/items are placed in a row (facing north/south or left/right).
- Example: “A sits to the left of B, but right of C.”
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Circular/Polygonal Arrangement
- People/items arranged around a circle or polygon, facing inward/outward.
- Example: “X sits second to the right of Y, who faces the center.”
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Floor/Building Arrangement
- People live on different floors of a building, with positional constraints.
- Example: “A lives above B but below C.”
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Distribution Problems
- Assigning people to categories (jobs, subjects, fruits, colors, etc.) with conditions.
- Example: “Five friends each like a different fruit.”
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Hybrid Problems
- Combination of arrangement + distribution.
- Example: “Eight people sit around a table, each working in a different company.”
How to Solve Step by Step
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Draw a structure
- Row, circle, table, or floor diagram to map placements.
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Place definite clues first
- Start with fixed positions like “A sits at one end.”
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Use relative clues
- Translate clues like “to the left of,” “two away from,” into diagram placements.
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Track negative clues
- Mark restrictions (e.g., “X does not sit next to Y”).
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Cross-check consistency
- Ensure all clues fit; if contradictions arise, restart with alternate casework.
Conceptual Tips and Common Mistakes
- Direction traps: Facing north vs facing south flips left/right orientation.
- Counting positions wrong: Always count inclusively/exclusively as per clue wording.
- Multiple possibilities: Keep parallel cases alive until eliminated.
- Mixing categories: In distribution problems, carefully track which attributes belong to whom.
- Time management: These puzzles are lengthy—use elimination wherever possible.
Examples
Example 1 — Linear Arrangement
Six people A–F sit in a row. A is left of B, C is right of D, and E sits at one end.
Answer: One valid sequence is E – A – B – D – C – F.
Example 2 — Circular Arrangement
Eight friends sit around a circle facing center. X sits second to the right of Y, and Z is opposite Y.
Answer: Place Y first, then map X and Z accordingly → full circle solved.
Example 3 — Floor Arrangement
Five people live on floors 1 to 5. A lives above B, but below C. D is not on the top floor.
Answer: Possible order: B (1), A (2), C (3), D (4), E (5).
Example 4 — Distribution Puzzle
Four students study different subjects: Math, Physics, Chemistry, Biology.
- A does not study Math.
- B studies Biology.
- C studies Physics.
Answer: A = Chemistry, B = Biology, C = Physics, D = Math.