Floor / Building Puzzle — Study Notes for IBPS PO Prelims

Overview

Floor or Building puzzles are among the most frequently tested puzzle types in IBPS PO Prelims. In these problems, you must arrange 5–8 persons across numbered floors of a building based on a set of conditions. The floors are typically numbered from bottom (Floor 1) to top (Floor 7 or 8).

These puzzles test your ability to process multiple constraints simultaneously, use elimination, and build a logical arrangement step by step. They often appear as a set of 5 questions worth 5 marks—making them high-value if solved correctly. Mastering floor puzzles is essential because the same logic applies to other linear arrangement problems, and once you develop a systematic approach, you can solve them within 6–8 minutes consistently.

The key to success is identifying "definite information" first—clues that fix a person's exact position—and then using elimination to place remaining persons based on relative clues.

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Key Concepts

• **Floor numbering convention**: Unless stated otherwise, Floor 1 is the ground floor (bottom), and floor numbers increase upward. Always confirm this from the question.

• **Definite vs. relative clues**: Definite clues directly state a position ("P lives on Floor 4"). Relative clues compare positions ("Q lives above R" or "S is two floors below T").

• **"Above" and "below" interpretation**: "A lives above B" means A's floor number > B's floor number. It does not mean immediately above unless the word "just" or "immediately" is used.

• **Gap-based clues**: "There are two floors between X and Y" means exactly two floors separate them (e.g., floors 2 and 5, or 3 and 6).

• **Negative clues**: "P does not live on the topmost floor" eliminates one possibility—use these after positive placements narrow options.

• **Multiple variables**: Advanced puzzles add a second attribute (profession, colour, department). Solve the floor arrangement first, then map the second variable.

• **Case-splitting**: When two equally valid arrangements exist after initial clues, maintain both cases until a later clue eliminates one.

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Formulas / Key Facts

1. **Total persons = Total floors** in standard puzzles (no empty floors unless stated).

2. **"Between X and Y"**: If there are n floors between them, the difference in their floor numbers = n + 1.

3. **Immediate neighbours**: "Just above" or "immediately below" means floor difference = 1.

4. **Topmost floor = highest floor number**; Bottommost floor = Floor 1.