Puzzles — Study Notes for SBI Clerk (Prelims)
Overview
These questions test your ability to organize scattered information, apply constraints logically, and arrive at a definite arrangement or comparison.
In SBI Clerk Prelims, puzzles remain at a moderate difficulty level — usually involving a single variable (like floors or days) with 5–7 persons. The key to scoring well is not brilliance but systematic practice — learning to extract conditions, build tables, and eliminate impossibilities step by step.
Mastering puzzles directly impacts your overall Reasoning score. A student who can confidently solve 2–3 puzzle sets in the exam gains a significant edge, as these questions come in clusters of 3–5 linked items.
Key Concepts
- Single-variable vs Multi-variable: SBI Clerk Prelims mostly tests single-variable puzzles (one attribute to arrange, like floors). Multi-variable puzzles (floor + department + age) appear rarely at this level.
- Definite vs Indefinite Information: Start solving from definite clues (e.g., "A lives on floor 3") before tackling indefinite ones (e.g., "B lives above C").
- Positive and Negative Conditions: "A is on floor 5" is positive; "A is not on floor 5" is negative. Mark negatives with crosses (✗) in your table.
- Relative Positioning: Terms like "immediately above," "two floors below," "between X and Y" define relative positions. Distinguish between "above" (anywhere higher) and "immediately above" (exactly one floor higher).
- Boundary Constraints: In floor puzzles, the topmost and bottommost floors have special constraints — only one neighbor each.
- Either-Or Conditions: When a clue gives two possibilities, create branches and test which one leads to a valid solution without contradictions.
- Linked Clues: Often, two or three clues connect through a common person. Identify these chains to build larger portions of the arrangement.
- Elimination Method: When direct placement fails, list all possibilities and eliminate those violating any condition.
Formulas / Key Facts
| Puzzle Type | What to Determine | Common Constraint Words |
|---|---|---|
| Floor Puzzle | Who lives on which floor (numbered 1 to n) | Above, below, immediately above, gap of two floors |
| Day/Month Scheduling | Who is assigned to which day or month | Before, after, on Monday, not on adjacent days |
| Box/Stack Puzzle | Order of boxes from top to bottom | On top of, below, immediately below, at the bottom |
| Comparison Puzzle | Rank persons by age, height, marks | Older than, shorter than, between X and Y |
| Circular Arrangement | Seating positions around a table | Facing center, left of, opposite to, immediate neighbor |
| Linear Arrangement | Row seating (single or double row) | Left end, right of, sits third from left |
Critical Fact: In SBI Clerk Prelims, most puzzles involve 5–7 persons and one arrangement variable. Solving time target: 4–6 minutes per set (including all linked questions).
Worked Examples
Example 1: Floor Puzzle
Problem: Six persons — P, Q, R, S, T, U — live on six floors numbered 1 (ground) to 6 (top).
- T lives on floor 4.
- Q lives immediately below P.
- R lives above T but not on the topmost floor.
- S does not live on floor 1 or 6.
- U lives below T.
Solution:
Step 1: Place definite information.
- T → Floor 4
Step 2: Apply "R lives above T but not on topmost."
- R can be on floor 5 only (floor 6 is topmost, ruled out).
- R → Floor 5
Step 3: "U lives below T" means U is on floor 1, 2, or 3.
Step 4: "S does not live on floor 1 or 6."
- S can be on floors 2, 3, or but floors 4 and 5 are taken.
- S → Floor 2 or 3
Step 5: "Q lives immediately below P."
- This pair occupies consecutive floors. Remaining floors: 1, 2, 3, 6.
- Possible pairs: (Q on 1, P on 2), (Q on 2, P on 3), (Q on 3, P on 6... but then U must fit in 1, 2).
Testing: If Q=2, P=3 → S must be on remaining floor among 1, 6. But S ≠ 1 or 6. Contradiction.
If Q=1, P=2 → S and U share floors 3 and 6. S ≠ 6, so S=3, U=6. But U must be below T (floor 4). U=6 violates this. Contradiction.
If Q=3, P=6 → Remaining: 1, 2 for S and U. S ≠ 1, so S=2, U=1. Check: U=1 is below T=4. Valid!
Final Arrangement:
| Floor | Person |
|---|---|
| 6 | P |
| 5 | R |
| 4 | T |
| 3 | Q |
| 2 | S |
| 1 | U |
Example 2: Day Scheduling
Problem: Five persons — A, B, C, D, E — have meetings on five consecutive days, Monday to Friday.
- B has a meeting on Wednesday.
- A has a meeting before C but after D.
- E does not have a meeting on Monday or Friday.
Solution:
Step 1: B → Wednesday
Step 2: "A before C but after D" means D...A...C (in that order).
Step 3: E ≠ Monday, E ≠ Friday → E is on Tuesday, Wednesday, or Thursday. But Wednesday = B. So E = Tuesday or Thursday.
Step 4: Fit D, A, C around these constraints.
- If E = Tuesday: Monday is D or part of D-A-C sequence.
- D-A-C needs three days. Available: Mon, Thu, Fri.
- D = Mon, A = Thu, C = Fri. Valid!
- Verify: E = Tuesday, B = Wednesday. All conditions satisfied.
Answer: Mon=D, Tue=E, Wed=B, Thu=A, Fri=C
Common Mistakes
- Confusing "above" with "immediately above": "X lives above Y" allows any floor higher than Y. "Immediately above" means exactly one floor higher. Fix: Underline the word "immediately" whenever you see it.
- Ignoring negative conditions midway: Students place persons but forget earlier "X ≠ floor 3" conditions. Fix: Mark all negatives with ✗ in your table before you start placing.
- Not testing both branches of either-or clues: When two possibilities exist, students assume one and proceed without verification. Fix: Quickly test the other branch if you hit a dead end.
- Miscounting gaps: "Two floors above" means a gap of one floor between them (e.g., floor 2 and floor 4). Fix: Use your fingers or draw lines to count physically.
- Starting with indefinite clues: Jumping to "A is above B" before using "C is on floor 5" wastes time. Fix: Always scan for definite placements first.
Quick Reference
- Always draw a table first — floors as rows, persons to be filled.
- Mark all negative conditions (✗) before placing any person.
- Start from definite clues, then link relative clues to them.
- "Immediately" = exactly one position apart; "above/below" = anywhere in that direction.
- Target time: 4–6 minutes per puzzle set (3–5 questions).
- Check all conditions once after completing the arrangement — catches silly errors.