Floors
Comprehensive notes, formulas, and practice questions for Floors.
Floors
Floor Puzzles
What is a Floor Puzzle
A floor puzzle gives you 4–6 people and a building with the same number of floors (usually numbered 1 = ground floor upward). A set of clues tells you partial information about who lives where. You must assign exactly one person to each floor.
Draw a vertical grid — floors down the left side, person names across the top — and tick or cross each cell as you work through the clues.
Step-by-Step Method
- Draw a table: rows = floor numbers (1 at bottom, 5 at top); columns = people.
- Mark absolute clues first — e.g., "Aryan lives on floor 3" → place Aryan on 3 immediately.
- Mark relative clues as inequalities — e.g., "Meera lives above Raj" → Meera's floor > Raj's floor.
- Use elimination: once someone is placed, cross them out of all other floors.
- Chain clues together — if A is above B and B is on floor 2, A must be on 3, 4, or 5.
- Repeat until all five floors are filled.
Worked Examples
Example 1 (5 people, 5 floors): People: Arya, Ben, Cleo, Dev, Eva. Floors 1–5. Clues:
- Ben is on floor 4.
- Arya is directly above Cleo.
- Dev is on the ground floor.
- Eva is above Ben.
Step 1: Place Dev on floor 1. Place Ben on floor 4. Eva above 4 → Eva on floor 5. Step 2: Arya directly above Cleo. Remaining floors: 2 and 3. So Cleo on 2, Arya on 3. Result: Dev-1, Cleo-2, Arya-3, Ben-4, Eva-5.
Example 2 (4 people, 4 floors): People: Anil, Bina, Charu, Disha. Floors 1–4. Clues:
- Charu is not on floor 1 or 4.
- Anil is two floors above Bina.
- Disha is on an odd-numbered floor.
Anil is two above Bina: pairs are Bina=1/Anil=3 or Bina=2/Anil=4. Disha is on an odd floor: 1 or 3. Charu is on 2 or 3. Try Bina=1, Anil=3: Disha must be on odd floor; floor 1 taken → Disha on 3, but Anil is on 3. Conflict. Try Bina=2, Anil=4: Disha on 1 or 3. Charu on 2 or 3, but 2 is Bina's → Charu on 3. Disha on 1. Result: Disha-1, Bina-2, Charu-3, Anil-4.
Common Traps
- "Above" vs "directly above" — "directly above" means exactly one floor higher; plain "above" means any higher floor.
- Forgetting the bottom is floor 1 — some questions say "ground floor" which equals floor 1.
- Placing someone without checking all constraints — always verify the full clue list after each placement.
Quick Check
- Five people: Kia, Leo, Mia, Nat, Omar. Kia is on floor 2. Mia is directly above Leo. Omar is on the top floor (5). Nat is between Kia and Mia. Where is Leo?
- In a 4-floor building: Priya is higher than Qais; Riya is on floor 1; Qais is directly above Riya. What floor is Priya on?
(Answers: 1 → Leo on floor 3 [Nat on 3? recalculate: Kia=2, Omar=5; Nat between Kia and Mia → Mia directly above Leo, Nat=3 so Mia=4, Leo=3 — Leo on floor 3]; 2 → Priya on floor 3 or 4; Qais=2, so Priya on 3 or 4)
Key Takeaways (TL;DR)
- What is a Floor Puzzle
- Step-by-Step Method
- Worked Examples
- Common Traps
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