Puzzles: Reasoning Ability Notes for Chandigarh PSC

📚 Chandigarh PSC – Reasoning Ability

Topic: Puzzles

Puzzles are a popular section in reasoning tests. They test your ability to think logically, spot patterns, and solve problems using deduction.

1️⃣ Simple Explanation

Term	What it Means	Quick Example
Logic Puzzle	Uses statements + deduction to find a hidden fact.	“If A is left of B, and B is right of C, who is at the extreme left?”
Seating Arrangement	Arranges people/items in a line or circle based on given clues.	“Chef sits between the baker and the painter.”
Number Sequence	Identifies the rule that generates a series of numbers.	2, 5, 10, 17, _? → 26 (add 3, 5, 7, 9…)
Word/Letter Puzzle	Finds the missing word, letter or pattern.	“DOG → EIG, FIND THE NEXT.”
Cross‑Number / Cross‑Word	Numbers/words intersect like a crossword.	“Fill 2×2 grid with numbers that satisfy row & column sums.”
Time/Distance Puzzle	Uses speed, time, and distance equations.	“Two cars start at 0 km at the same time, one travels 60 km/h, the other 90 km/h. When will they meet?”

2️⃣ Key Points to Remember

#	Concept	How to Apply
1	Read Carefully	Every word can be critical. Highlight or underline important keywords.
2	Make a List	Write down all given facts separately (e.g., “A is older than B”, “C sits between D & E”).
3	Use Venn‑Diagrams / Tables	Visualise relationships – especially useful for seating and grouping puzzles.
4	Work Backwards	If a result is asked (e.g., “Who sits at the 4th seat?”), start from the end and trace back.
5	Check Consistency	After a solution, re‑read the clues to confirm no contradictions.
6	Time Management	Solve 2–3 easier puzzles first to gain momentum.
7	Pattern Recognition	For sequences, test arithmetic, geometric, prime numbers, squares, cubes, or mixed patterns.
8	Elimination	Remove impossible options early to reduce choices.

3️⃣ Worked Example

Puzzle (Seating Arrangement)

Five friends A, B, C, D, E are to sit in a row.

A sits to the immediate left of B.

C sits somewhere to the right of D.

E sits in the middle.

D is not at any end.

B is not at the third seat.
Question: Who sits at the 2nd seat?

Step‑by‑Step Solution

Middle Seat
- Seat layout: _ _ E _ _ (E occupies seat 3).
A left of B
- Possible pairs: (A,B) can be (1,2), (2,3), (3,4), or (4,5).
- Since seat 3 is E, pair (2,3) or (3,4) is impossible.
- So only (1,2) or (4,5) remain.
D not at any end
- Ends are seats 1 and 5.
- Therefore D can be in seats 2, 3, or 4.
C right of D
- If D is seat 2 → C must be seat 4 or 5.
- If D is seat 3 → C must be seat 4 or 5.
- If D is seat 4 → C must be seat 5.
B not at seat 3
- Seat 3 is already E, so fine.
Consider Pair (1,2) for (A,B)
- Seat 1 = A, seat 2 = B.
- Then D cannot be seat 2 (occupied by B).
- D could be seat 3 or 4.
- If D seat 3 → C seat 4 or 5.
- But seat 3 is E – impossible.
- If D seat 4 → C seat 5.
- Check: seats → 1:A, 2:B, 3:E, 4:D, 5:C → all clues satisfied!
Consider Pair (4,5) for (A,B)
- Seat 4 = A, seat 5 = B.
- D cannot be seat 5 (occupied).
- D could be seat 2 or 3.
- If D seat 2 → C seat 4 or 5 (but 4 is A).
- If D seat 3 → C seat 4 or 5 (but 4 is A).
- None works.

Thus, the only valid arrangement is
Seat 1: A | Seat 2: B | Seat 3: E | Seat 4: D | Seat 5: C

Answer: The 2nd seat is occupied by B.

4️⃣ Quick Revision Summary

Topic	Quick Tips
Logic Puzzles	Identify “if‑then” statements, create a truth table.
Seating Arrangements	Draw a line, place definite positions first (middle, ends).
Number Sequences	Test +, –, ×, ÷, prime, squares, cubes, alternating patterns.
Word/Letter Puzzles	Look for anagrams, alphabet positions, word lengths.
Cross‑Number	Use row/column sums, start with cells having most constraints.
Time/Distance	Use the formula `distance = speed × time`. Solve for unknowns.
General Strategy	1) Read & note all facts. 2) Visualise. 3) Work backwards or forwards. 4) Verify.

Practice Tip: Solve at least one puzzle of each type every