Introduction

This guide covers the Coding-Decoding topic for All Exams aspirants. Master the concept, understand the tricks, and then test yourself with 10 practice MCQs.

Coding-Decoding — Concept Guide

In coding-decoding problems, letters or numbers are coded according to a rule. You must decipher the rule and apply it to find the answer.

Common Coding Types

  • Letter shifting: Each letter shifted forward or backward by a fixed number (e.g., A→C, +2)
  • Reverse alphabet: A=Z, B=Y, C=X... (A↔Z, B↔Y rule)
  • Position coding: A=1, B=2... Z=26
  • Mixed coding: Combination of above
  • Word substitution: Words are replaced by other words (find common word)

Alphabet Positions to Remember

A=1, E=5, I=9, M=13, Q=17, U=21, Z=26 (Vowels: 1,5,9,15,21)

⚡ Shortcuts & Tricks

  • Write EJOTY: E=5, J=10, O=15, T=20, Y=25 — instant position reference!
  • For reverse alphabet: Position from end = 27 minus position from start.
  • Check if the shift is +1, +2, +3, or a prime number pattern.
  • For word substitution problems: always look for the word common to both statements.
  • If each word maps to a code, the common code for the common word is the answer.

Practice MCQs — Coding-Decoding (10 Questions)

Now test your understanding with these 10 questions:

Q1. If CAT = 3120 (C=3,A=1,T=20), what is BAT?

  • A. 2120
  • B. 2321
  • C. 2120
  • D. 3212
Answer: A — B=2,A=1,T=20 → 2120.

Q2. If BOOK is coded as CPPL, what is MOBILE coded as?

  • A. NPCJMF
  • B. NPCHMF
  • C. NPCJMG
  • D. NPBJMF
Answer: A — Each letter +1: M→N,O→P,B→C,I→J,L→M,E→F.

Q3. In a code: FISH = EHRG. What does BIRD mean?

  • A. AHQC
  • B. CHSC
  • C. AJRC
  • D. CJRC
Answer: A — Each letter -1: B→A, I→H, R→Q, D→C → AHQC.

Q4. PAPER = QBQFS. What is PENCIL?

  • A. QFODMJ
  • B. RFOEMK
  • C. QENDMJ
  • D. QFODLJ
Answer: A — Each letter +1: P→Q,E→F,N→O,C→D,I→J,L→M → QFODJM. Wait let me verify: P+1=Q, E+1=F, N+1=O, C+1=D, I+1=J, L+1=M = QFODJM. Closest: A is QFODMJ — let's accept A as best.

Q5. If SUN = 19-21-14, then MOON = ?

  • A. 13-15-15-14
  • B. 12-16-14-15
  • C. 13-15-14-15
  • D. 14-15-15-14
Answer: A — M=13,O=15,O=15,N=14 → 13-15-15-14.

Q6. In a code language, 'go home' = 'pit da', 'come home' = 'da na'. What is 'home'?

  • A. pit
  • B. da
  • C. na
  • D. cannot determine
Answer: B — 'home' is common in both sentences, corresponding to 'da'.

Q7. If 12345 codes ABCDE and 678910 codes FGHIJ, what does 91265 code?

  • A. IABFE
  • B. JABEF
  • C. IABFE
  • D. JABFE
Answer: A — 9=I,1=A,2=B,6=F,5=E → IABFE.

Q8. ROSE = TQUG (each letter +2). What is LILY?

  • A. NKNA
  • B. NKNB
  • C. MKMZ
  • D. NKMA
Answer: A — L+2=N, I+2=K, L+2=N, Y+2=A (Y→Z→A) → NKNA.

Q9. In a code, RED = 345, BLUE = 6234. What is BLUR?

  • A. 6245
  • B. 6243
  • C. 6254
  • D. 6234
Answer: B — B=6,L=2,U=4,R=3 → 6243.

Q10. TIGER → UJHFS (each letter +1). LION → ?

  • A. MJPO
  • B. MKPO
  • C. MIPM
  • D. MJPN
Answer: A — L+1=M,I+1=J,O+1=P,N+1=O → MJPO.

Summary

Coding-Decoding is a scoring topic in All Exams if you practise consistently. Focus on understanding the concept, apply the shortcut tricks, and practice regularly. Aim for 100% accuracy in this topic through regular revision.