Coding‑Decoding – Reasoning Ability
Barc Recruitment – Practice & Revision Notes
1. Simple Explanation
Coding‑Decoding is a type of verbal reasoning question that tests your ability to understand a code (a set of patterns, symbols, or relationships) and use it to decode a new set of data.
- Code: The hidden rule that links a set of items (words, numbers, shapes, letters, etc.) to another set.
- Decode: Apply that rule to a new item to find its counterpart.
Think of it as a translation between two languages that you must discover first.
2. Key Points to Remember
| # | Point | Why It Matters |
|---|---|---|
| 1 | Identify the pattern | Look for common attributes (length, position, repetition, alphabetical order, etc.) |
| 2 | Check all elements | Compare both sides of the code (e.g., word ↔ word, letter ↔ number). |
| 3 | Look for multi‑step rules | One change may be followed by another (e.g., swap + shift). |
| 4 | Validate with all pairs | A valid rule should work for every given pair. |
| 5 | Keep it simple | Start with the simplest rule; complexity is usually a red‑flag. |
| 6 | Test the rule | Before finalising, apply the rule to the question item and see if it gives a unique, logical answer. |
| 7 | Use elimination | If more than one rule fits, discard the one that gives ambiguous or impossible results. |
| 8 | Time management | Spend 30–45 s on pattern recognition; the rest is verification. |
3. Worked Example
Problem Statement
| Code | Decoded |
|---|---|
APPLE |
X |
BANANA |
Y |
CHERRY |
Z |
Find the decoded value for DATE.
(Options: 1. 4 2. 5 3. 6 4. 7)
Step‑by‑Step
| Step | Action | Observation |
|---|---|---|
| 1. Count letters | APPLE → 5, BANANA → 6, CHERRY → 6 |
Lengths: 5,6,6 |
| 2. Look at vowels | APPLE → 2 (A,E), BANANA → 3 (A,A,A), CHERRY → 2 (E,E) |
Vowel counts: 2,3,2 |
| 3. Try simple sums | 5+2=7, 6+3=9, 6+2=8 → no pattern | |
| 4. Check alphabetical position of first letter | A=1, B=2, C=3 | 1,2,3 |
5. Compute Length - FirstLetterPosition |
5-1=4, 6-2=4, 6-3=3 | Gives 4,4,3 – not consistent |
6. Consider VowelCount × Length |
2×5=10, 3×6=18, 2×6=12 | Not helpful |
| 7. Look at number of distinct letters | APPLE → 4, BANANA → 3, CHERRY → 5 |
4,3,5 |
8. Notice Length - DistinctLetters |
5-4=1, 6-3=3, 6-5=1 | 1,3,1 – still no pattern |
9. Try Alphabetical index of last letter |
APPLE → E=5, BANANA → A=1, CHERRY → Y=25 |
5,1,25 |
10. Check Length + Alphabet index of last letter |
5+5=10, 6+1=7, 6+25=31 | Not matching |
| 11. Focus on vowel positions (1st, 2nd, 3rd) | APPLE: positions 1(A) & 5(E) → 1+5=6; |
6 |
BANANA: positions 2,4,6 → 2+4+6=12 |
12 | |
CHERRY: positions 3,5 → 3+5=8 |
8 | |
Pattern: Sum of vowel positions → 6,12,8 |
||
| 12. Check consistency | All computed sums are integers; we can use them as decoded values. | |
13. Decode DATE |
Vowels: A=2, E=4 → 2+4=6 | So decoded value = 6. |
Answer: 3. 6
Why This Works
- The rule “sum of the alphabetical positions of the vowels” applies to ALL given pairs.
- It yields a unique integer for each word.
- When applied to the question word, it produces a valid choice from the options.
4. Quick Revision Summary
| Topic | Take‑away |
|---|---|
| Pattern hunting | Examine lengths, distinct letters, vowels, positions, alphabetical indices. |
| Rule validation | Must satisfy every given pair. |
| Simplicity | Start with the simplest rule; add complexity only if needed. |
| Verification | Always test the rule on the question item. |
| Common traps | Over‑fitting, ignoring all pairs, assuming a rule that works for some but not all. |
| Time tip | 30 s to spot pattern, 15 s to verify, 15 s to answer. |
Practice Tip:
Create your own mini‑coding‑decoding sets (e.g., DOG → 3, CAT → 3, MOUSE → 5) and try to deduce the rule. The more you practice, the faster you’ll spot the hidden logic.
Good luck, and keep decoding!