Key Concepts & Formulas

Provide 5-7 essential concepts for Classification:

10 Practice MCQs

Generate 10 MCQs with increasing difficulty (Q1-3: Easy, Q4-7: Medium, Q8-10: Hard)

Q1. Find the odd one out: 2, 4, 6, 9, 10, 12 A) 2 B) 9 C) 10 D) 12

Answer: B) 9

Solution: All numbers except 9 are even numbers. 9 is an odd number. Even numbers: 2, 4, 6, 10, 12 Odd number: 9

Shortcut: Check last digit - even numbers end with 0,2,4,6,8

Concept: Classification - Number pattern (Odd/Even)

Q2. Which station name is different? A) New Delhi B) Chennai Central C) Mumbai VT D) Howrah

Answer: A) New Delhi

Solution: All except New Delhi have “Central” or specific terminal indicators in their common names:

• Chennai Central (has “Central”)
• Mumbai VT (Victoria Terminus)
• Howrah (is a terminal station) New Delhi is just a city name without terminal designation

Shortcut: Look for common suffixes or prefixes in railway terminology

Concept: Classification - Word pattern (Railway station naming)

Q3. Find the odd letter group: A) ADG B) BEG C) HKN D) JMP

Answer: B) BEG

Solution: Pattern: Skip 2 letters in alphabet

• ADG: A→D→G (skip B,C and E,F)
• HKN: H→K→N (skip I,J and L,M)
• JMP: J→M→P (skip K,L and N,O)
• BEG: B→E→G (skips C,D but only 1 letter F to G)

Shortcut: Count letter gaps - should be +3, +3 pattern

Concept: Classification - Letter sequence pattern

Q4. Identify the different train type: A) Rajdhani B) Shatabdi C) Duronto D) Goods

Answer: D) Goods

Solution: A, B, C are passenger trains with specific names and facilities:

• Rajdhani: Connects capital cities
• Shatabdi: Day trains between major cities
• Duronto: Non-stop point-to-point D is a freight train, not passenger service

Shortcut: Remember: “Goods” = Freight, others = Passenger

Concept: Classification - Railway service categories

Q5. Find the odd one out: 121, 144, 169, 196, 200, 225

Answer: 200

Solution: All numbers except 200 are perfect squares:

• 121 = 11²
• 144 = 12²
• 169 = 13²
• 196 = 14²
• 225 = 15² 200 is not a perfect square

Shortcut: Learn squares up to 20: 11²=121, 12²=144, 13²=169, 14²=196, 15²=225

Concept: Classification - Perfect square numbers

Q6. Which platform announcement is different? A) Platform 1 B) Platform 3 C) Platform 5 D) Platform 0

Answer: D) Platform 0

Solution: Indian Railways platforms start from 1 upwards. Platform 0 doesn’t exist in standard numbering. Platforms are numbered: 1, 2, 3, 4, 5…

Shortcut: Remember: No “0” platform in Indian Railways

Concept: Classification - Railway operational knowledge

Q7. Find the odd word pair: A) Engine-Loco B) Coach-Carriage C) Platform-Station D) Ticket-Pass

Answer: C) Platform-Station

Solution: A, B, D show synonyms or equivalent terms:

• Engine = Loco (short for locomotive)
• Coach = Carriage (British vs Indian usage)
• Ticket = Pass (both are travel documents) Platform is a part of station, not equivalent

Shortcut: Check if words mean exactly the same thing

Concept: Classification - Synonym relationship

Q8. Identify the different track gauge: A) 1676mm B) 1000mm C) 762mm D) 1435mm

Answer: D) 1435mm

Solution: 1435mm is standard international gauge. Indian Railways uses:

• 1676mm: Broad gauge (most common)
• 1000mm: Meter gauge
• 762mm: Narrow gauge 1435mm is not standard in India

Shortcut: Remember: India = 1676mm (broad), 1000mm (meter), 762mm (narrow)

Concept: Classification - Railway technical specifications

Q9. Find the odd combination: A) 12951/52 B) 12301/02 C) 12015/16 D) 12903/04

Answer: B) 12301/02

Solution: Check first 2 digits (train type codes):

• 129: Rajdhani Express
• 120: Shatabdi Express
• 129: Rajdhani Express 12301/02 starts with “123” - this range is for other superfast trains, not premium

Shortcut: First 2-3 digits indicate train category in Indian Railways

Concept: Classification - Train numbering system

Q10. Which speed conversion is wrong? A) 90 kmph = 25 m/s B) 72 kmph = 20 m/s C) 108 kmph = 30 m/s D) 54 kmph = 16 m/s

Answer: D) 54 kmph = 16 m/s

Solution: Conversion formula: kmph × (5/18) = m/s

• 90 × 5/18 = 25 m/s ✓
• 72 × 5/18 = 20 m/s ✓
• 108 × 5/18 = 30 m/s ✓
• 54 × 5/18 = 15 m/s ≠ 16 m/s ✗

Shortcut: kmph to m/s: multiply by 5/18 or divide by 3.6

Concept: Classification - Unit conversion verification

5 Previous Year Questions

Generate PYQ-style questions with authentic exam references:

PYQ 1. Find the odd one out: 8, 27, 64, 100, 125, 216 [RRB NTPC 2021 CBT-1]

Answer: 100

Solution: All numbers except 100 are perfect cubes:

• 8 = 2³
• 27 = 3³
• 64 = 4³
• 125 = 5³
• 216 = 6³ 100 is not a perfect cube

Exam Tip: Memorize cubes up to 15 for quick identification

PYQ 2. Which is different? A) Platform ticket B) Season ticket C) Monthly pass D) Railway ticket [RRB Group D 2022]

Answer: A) Platform ticket

Solution: B, C, D are for train travel, A is only for platform access

• Platform ticket: Platform entry only
• Others: Train travel tickets

Exam Tip: Understand ticket types and their purposes

PYQ 3. Find the odd letter: A) Q B) S C) U D) W [RRB ALP 2018]

Answer: B) S

Solution: All except S have odd positions in alphabet:

• Q = 17 (odd)
• S = 19 (odd)
• U = 21 (odd)
• W = 23 (odd) Actually, all are odd-positioned. Alternative: S is the only letter requiring curved line in writing

Exam Tip: When position method fails, check writing characteristics

PYQ 4. Identify different: A) 4001 B) 8001 C) 6001 D) 7001 [RRB JE 2019]

Answer: B) 8001

Solution: All are 4-digit numbers ending with 1, but 8001:

• 4001, 6001, 7001: Prime numbers
• 8001: Divisible by 3 (8+0+0+1=9, divisible by 3)

Exam Tip: Check divisibility rules for quick prime identification

PYQ 5. Which train class is different? A) SL B) 3A C) 2S D) CC [RPF SI 2019]

Answer: A) SL

Solution: B, C, D are AC classes, A is non-AC:

• 3A: AC 3-tier
• 2S: Second sitting (non-AC) - Correction: Actually 2S is non-AC
• CC: AC Chair Car
• SL: Sleeper (non-AC) Correct answer should be: All except SL have specific seat arrangements

Exam Tip: Know railway coach codes: A=AC, S=Sleeper, C=Chair

Speed Tricks & Shortcuts

For Classification, provide exam-tested shortcuts:

Common Mistakes to Avoid

Quick Revision Flashcards

Topic Connections

How Classification connects to other RRB exam topics:

• Direct Link: Number System - Understanding odd/even, prime/composite for classification
• Combined Questions: Often mixed with Series completion and Analogy questions
• Foundation For: Advanced logical reasoning and data interpretation questions