Puzzles (Logical): Concepts, Formulas, and Clear Examples
Logical puzzles pack constraints—schedules, floors, professions, colors—into a paragraph. You build a table and fill certainties first, then propagate ‘either/or’ until one row is forced.
Placement puzzles reward systematic grids (person × attribute) and elimination. Never guess; each MCQ option should be provable from the chain. Start with the most constrained clue (unique pairing, ‘only one,’ fixed slot).
Grid setup
- Rows = people or slots; columns = attributes (city, pet, rank).
- Use ticks for sure, crosses for impossible.
Ordering puzzles (rank, height, age)
Convert ‘A taller than B’ into inequalities. Chain them: if A > B > C, fill order line before attributes.
Example — Three-person order
Clues: Ali above Ben; Cara not top; Ben not bottom.
If Ali > Ben and Ben not bottom, Ben middle unless Cara forces otherwise. Cara not top → Cara bottom or middle. Work cases—only one orders all three consistently.
Floor and position puzzles
- Draw vertical floors 1..n; ‘directly above’ means floor +1.
- ‘Not on corner’ eliminates end slots.
Day/month scheduling
- Calendar grid: Mon–Sun × person.
- ‘Two days before’ fixes relative offset.
Either/or and bifurcation
When stuck, split on one unknown (A in Mumbai or Delhi) and prune branch that violates a clue.
MCQ validation
- Plug each option into all clues—first failure eliminates.
Step-by-step method for exam questions
- List entities and attributes; draw the table.
- Process clues with ‘is,’ ‘never,’ ‘only’ before vague ones.
- Mark direct fills; propagate eliminations.
- Use inequality chains for order puzzles.
- If two cases remain, test against remaining clues.
- Answer; optionally verify by backsolving options.
Formula cheat sheet
| Situation | Formula | When to use |
|---|---|---|
| Unique pairing | One row/column forced | First pass |
| Either A or B | Split cases | Stuck grid |
| Order chain | / compile | Ranking clues |
| Floor above | Building puzzles | |
| Option check | All clues must hold | Final verify |
Frequently asked questions
Guess when time is low?
Backsolve MCQ options instead of random guessing.
Redundant clues?
Often the last clue confirms uniqueness; still use it to verify.
How big can grids get?
4×4 common; same method scales—never skip writing.
Practice on this platform
Use 4 practice sets (10 MCQs, detailed solution after each answer) and 2 timed mocks (20 minutes) on this topic to convert formulas into speed and accuracy.