🚀 Quick Revision Sheet – Coding-Decoding
🔑 Golden Rule
“Treat letters as numbers (A=1 … Z=26) & play with ±1, ±2, reverse, opposite.”
đź“Ś 6 High-Frequency Patterns (Railway Favourite)
| Pattern Name | Rule (Forward A→Z) | Reverse (Z→A) | Memory Trick |
|---|
| +1 (Forward) | Each letter +1 | -1 | “Add 1 → Ahead” |
| +2 (Skip) | Each letter +2 | -2 | “Skip a seat” |
| Reverse Word | Whole word reversed | Same | “Mirror writing” |
| Opposite letter | A↔Z, B↔Y … (sum=27) | Same | “27 minus position” |
| Vowel→Consonant shift | V+1, C+2 (or vice-versa) | — | “Vowels are VIP (+1)” |
| Number code | Position nos. concatenated | Reverse digits | “Read like barcode” |
🧠Mnemonics
- A-Z = 1-26 → “All Boys Can Dance … Zebra” (count on fingers).
- Opposite letter → AZ BY CX DW EV … (read pairs: A-Z, B-Y… sum 27).
- Reverse word → “LAP ↔ PAL” (think friend’s name).
🎯 3-Step Railway Method
- Spot pattern: look at 1st & last letter of given code.
- Convert to numbers (A=1…Z=26).
- Apply ±1, ±2, reverse, opposite → match with options.
📊 Quick Reference Table (A=1 … Z=26)
| Letter | A | B | C | D | E | F | G | H | I | J | K | L | M |
|---|
| No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| Letter | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
|---|
| No. | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 |
⚡ 10 Rapid-Fire MCQs
1. If CAT is coded as DBU, then DOG is?
**Answer:** EPH (+1 pattern)2. If RAIL → 91812, then PARK → ?
**Answer:** 1611811 (position numbers)3. If ZOO → ALL, then TOOL → ?
**Answer:** GLOO (opposite letter)4. If 12345 → VWXYZ, then 5 → ?
**Answer:** Z (last letter)5. If CUP → PCR, then PEN → ?
**Answer:** PGN (C-2, U-2, P-2 → reverse -2)6. If EARTH → VIZGS, then PLANET → ?
**Answer：** KORMVG (opposite letter)7. If 786 → PEN, then 687 → ?
**Answer:** NEP (digit swap)8. If FLAG → GMBH, then CODE → ?
**Answer:** DPEF (+1 each)9. If 5-12-1 → E-L-A, then 16-5-14 → ?
**Answer:** P-E-N10. If WATER → XBUFS, then FIRE → ?
**Answer:** GJSF (+1 each)
🎯 30-Second Hack: Spot vowels first—Railway sets 70 % codes around vowel shifts.
BETA
