Coding-Decoding finds the rule behind encoded messages. Direction Sense tracks movement on a compass. Both are solvable in under 90 seconds with the right method.
Coding-Decoding presents a coded message and asks you to find the original word — or vice versa. The code follows a specific rule (shift letters, reverse, swap pairs, etc.).
Direction Sense gives you a series of movements (go North 5 km, turn right, go 3 km...) and asks you the final position, distance from start, or direction faced.
Both are pattern-recognition problems that reward systematic approach over guessing.
| Code Type | Rule | Example |
|---|---|---|
| Letter Shift | Each letter moves +n or -n in alphabet | A→C (shift +2) |
| Reverse Alphabet | A↔Z, B↔Y... A becomes Z, B becomes Y | CAT → ZZG |
| Mirror | A=1, B=2... or A=Z, B=Y... | |
| Word Reversal | Reverse the word | CAT → TAC |
| Letter Substitution | Fixed substitution table | C=X, A=Y, T=Z |
| Symbol Code | Letters replaced by symbols/numbers | |
| Mixed Code | Combination of above |
Step 1: Compare coded and original word — count letters, note any obvious patterns.
Step 2: Map each letter → its code. Look for the shift rule.
Step 3: Verify the rule with all letters in the example.
Step 4: Apply the verified rule to the target word.
"If MANGO = PDQJR, find code for APPLE."
M → P (shift +3), A → D (+3), N → Q (+3), G → J (+3), O → R (+3).
Rule: Each letter shifts +3 in alphabet.
APPLE: A→D, P→S, P→S, L→O, E→H → Code = DSSOH.
"If CAT = FDB, find code for DOG."
C(3)→F(6): +3. A(1)→D(4): +3. T(20)→B(2): shift of -18? Hmm.
Let me reconsider: T(20)→B(2). What if the word is reversed first?
CAT reversed = TAC. T→F? No.
Try: C→F(+3), A→D(+3), T→B... T is 20th, B is 2nd. 20+3=23=W, not B.
Alternative: Code is reversed + shift. CAT→TAC→UBD? Not FDB.
Let me try: Reverse the code? FDB reversed = BDF. C→B? A→D? T→F?
Actually — CAT, standard position: C=3, A=1, T=20.
Code: F=6, D=4, B=2.
C=3→F=6 (+3). A=1→D=4 (+3). T=20→B=2 (20+3=23=W, or 20-18=2=B).
If we cycle back: Z=26, A=1. T(20)+3=23=W? Still not B.
Correct interpretation: F=6=3+3. D=4=1+3. B=2=20+3 mod 26? 23 mod 26 = 23. Not B.
The code F,D,B positions are 6,4,2. Original C,A,T positions are 3,1,20.
6-3=3, 4-1=3, 2-20=-18 (or equivalently 8 in reverse: 26-20+2=8... no).
Another approach: code positions 6,4,2 vs word positions 3,1,20.
Actually, the encoded letters in reverse are B,D,F = 2,4,6. Word = C,A,T = 3,1,20. Still doesn't click for T.
Lesson for students: If a pattern doesn't immediately resolve, try:
The key skill is systematic testing of possible rules.
"If CAT = 3120, find code for DOG."
C=3, A=1, T=20 (their alphabetical positions concatenated). So 3-1-20 = 3120. ✓
DOG: D=4, O=15, G=7 → Code = 41507 or 4157 (concatenated).
| Pattern observed | Likely rule |
|---|---|
| Code has same length | Letter-by-letter transformation |
| Code is shorter | Likely number substitution |
| Vowels unchanged | Only consonants transformed |
| Ascending/descending | Position-based shift |
| Letters seem random | Substitution cipher (look for key) |
North
↑
West ← · → East
↓
SouthTurning:
Step 1: Draw the starting point on paper.
Step 2: Follow each movement step, drawing the path.
Step 3: At the end, identify position relative to start.
Step 4: Calculate distance (use Pythagoras if at right angles).
"Rohan starts facing North. He walks 5 km. Turns right. Walks 3 km. Turns right. Walks 5 km. Where is he from start?"
Start (S) → North 5km → (A) → East 3km → (B) → South 5km → (C)Drawing:
C is 3 km East of S (the North 5 and South 5 cancel).
He is 3 km East of his starting point.
"Priya walks 6 km North, 8 km East. Find straight-line distance from start."
This forms a right triangle (North = 6, East = 8).
Hypotenuse = √(6² + 8²) = √(36+64) = √100 = 10 km.
(Pythagorean triple: 6-8-10.)
Trap 1: "Her right" vs "Your right"
Always use the person's perspective, not yours.
Trap 2: "Towards the sun"
Morning: Sun rises East. Evening: Sun sets West. Use time context.
Trap 3: Shadow direction
Shadow falls opposite to sun direction. Morning shadow falls West. Evening shadow falls East.
Trap 4: Turning multiple times
Track each turn cumulatively. After 4 right turns = back to original direction.
| Current | Turn Right | Turn Left | About Turn |
|---|---|---|---|
| North | East | West | South |
| East | South | North | West |
| South | West | East | North |
| West | North | South | East |
Coding:
Direction:
Coding-Decoding requires systematic pattern identification: compare original and code, find the shift/substitution rule, verify it fully, then apply. Direction sense requires drawing the path on paper and using the compass rose for turns. Distance from start uses Pythagoras for right-angle paths. These are two of the fastest LR question types when approached methodically.
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