Puzzles: Reasoning Ability Notes for Dadra & Nagar Haveli and Daman & Diu Police Sub-Inspector (SI)

Reasoning Ability – Puzzles

Dadra & Nagar Haveli & Daman & Diu Police Sub‑Inspector (SI)
Exam‑style study notes – “Puzzles”

1. Simple Explanation

What are Puzzles?	How do they appear?
A puzzle is a short, self‑contained problem that tests logic, pattern recognition, sequencing, or spatial reasoning.	They are given as a set of statements, numbers, or diagrams with a single, clear answer.
They usually require you to deduce an unknown from a few given facts.	Often appear as (a) “What comes next?”, (b) “Who has what?”, (c) “What is missing?”, (d) “How many?”

The key is to translate the words into logical relations and then eliminate impossibilities until only one possibility remains.

2. Key Points & Strategies

#	Strategy	Why it Works	Quick Tips
1	Read Carefully & Highlight	Mis‑reading a single word (“not”, “except”) can change the answer.	Mark “not” and “except” in red.
2	Identify Variables	Convert people, items, places into letters/variables.	e.g., A = Alice, B = Bob, N = Number of cars.
3	Create a Table or Grid	Visual representation eliminates contradictions fast.	Use a 2‑column table for two categories, or a 3‑column for three.
4	Use Elimination	Remove impossible pairs one by one.	Whenever a condition says “X cannot be Y”, cross‑out that cell.
5	Check for Logical Contradictions	If a deduction forces a conflict, the earlier assumption is wrong.	Look for “two people in same house” when “no two can be.”
6	Look for “Only One Possibility” Clues	Many puzzles give a fact that forces one unique arrangement.	“Only one person has a red bike.”
7	Work Backwards	Sometimes it’s easier to start from the answer and see what fits.	If you know the answer must be “5”, work out why 5 is the only one.
8	Keep a Checklist of Conditions	Prevent forgetting a constraint while solving.	Write each condition as a separate bullet.
9	Time Management	Allocate ~1–2 minutes for simple puzzles, 3–5 minutes for harder ones.	If stuck after 5 min, skip and revisit if time allows.
10	Practice Pattern Recognition	Many puzzles repeat the same logical pattern.	Notice when “A is above B” and “B is left of C” → “A is above-left of C.”

3. Worked Example

Puzzle (Typical of the exam)

**Five houses are in a row (from left to right).

The blue house is immediately to the left of the red house.

The green house is on the far right.

The yellow house is not next to the blue house.

The white house is somewhere to the right of the green house.

The red house is somewhere to the left of the white house.

The white house is the third house from the left.
Question: What color is the fourth house?**

Step‑by‑Step Solution

Step	Action	Result
1	Place the 5th house from the left (since “far right”).	5th = Green
2	Place the 3rd house from the left (white).	3rd = White
3	From 4) “White is somewhere to the right of Green” → Green must be left of White.	5th (Green) is right of 3rd (White) → Contradiction.
→ The assumption “5th = Green” is wrong.
4	The “far right” must be the 5th house as given, but Green cannot be 5th.
→ The only way to satisfy 4) is to put Green in the 4th house.	4th = Green
5	Because Green is 4th, White (3rd) is left of Green → satisfies 4).
6	From 1) “Blue is immediately left of Red”.
The only adjacent pair left is 1st & 2nd or 2nd & 3rd.
3rd is White, so Blue & Red must be 1st & 2nd.	1st = Blue, 2nd = Red
7	Check remaining constraints:
• 3) Yellow not next to Blue → Yellow cannot be 2nd.
• 5) Red left of White → Red(2nd) left of White(3rd) ✓
8	Only color left for 5th house is Yellow.	5th = Yellow

Answer: The 4th house is Green.
(Question actually asked for the 4th house, which we already found.)

4. Quick Revision Summary

Topic	What to Remember
Identify Variables	Turn people/items into letters or numbers.
Use a Table/Grid	Helps visualise and cross‑out impossibilities.
Eliminate	Remove all impossible pairings from the start.
Check Contradictions	If a condition is violated, backtrack.
Look for “Only One” clues	They usually pinpoint the answer quickly.
Practice Pattern Recognition	Many puzzles use the same logical templates.
Time Management	1–2 min for easy, 3–5 min for medium, skip if >5 min.

Quick Practice Questions

Seating Arrangement – 4 people