Coding Decoding Reasoning Notes


What does Coding Decoding mean?

Basically, coding is a system of transmitting information from one person to another without known to the third person.

The person receiving the signal or information is called the receiver, and he/she must know to decode the codes.

So, in questions related to coding-decoding, a word is coded in a particular pattern and the candidates are asked to find a similar pattern.

Rules to follow for a quick result-

  1. Memorize the English Alphabet with the positions.
  2. Memorize the forward/Backward order positions. A → Z & Z → Z
  3. Memorize the opposite of each Alphabet. Ex- Y opposite of B.
  4. If the sum of the two letters is 27, then both are opposite of each other. Ex – Y (25th position) opposite of B (2nd position). Here (25 + 2 = 27)
  5. Always approach the Question by writing the letters’ position.
  6. Make your own tricks to memorize the positions, the opposite, etc.
  7. The more you practice the more command you will get.

Types of Questions

  • Direct/Indirect Letter Coding
  • Number or Symbol Coding
  • Substitution Coding
  • Message decoding from words or numerals

Read Also: Short Notes of DICE Reasoning


Direct/Indirect Letter Coding

Q. If DEW is written as FGY then how would LUX be written – (Indirect)

a) NVZ

b) NWY

c) NWZ – Correct (keeping a gap of one letter)

d) NXZ

Q. If DEW is written as FGY and LUX is written as NWZ then how would DELUXE be written – (Direct)

Answer – By directly interpretation – D → F, E → G, L → N, U → W, X → Z, E → G


Number Coding or Symbol Coding

Q. If KAKA is coded as 11-1-11-1 then how will you code PAPA?

Solution – Correct answer is 16-1-16-1

Explanation –

Since K → 11 (Alphabet position) & A → 1 (Alphabet position)

Similarly, P → 16 (alphabet position) & A → 1

Substitution Coding

Q. If a bucket is called tub, the tub is called glass, glass is called saucer, the saucer is called spoon, then which utensil will you use for drinking water?

Options- a) Saucer b) Glass c) Spoon d) None of these

Solution – Correct (a); Because here Saucer is called as glass.

Message Decoding from Words or Numerals

Q. In a certain code-

“min fin bin gin” means “trains are always late”

“gin din cin hin” means “drivers were always punished”

“bin cin vin rin” means “drivers stopped all trains”

“din kin fin vin” means “all passengers were late”

Then “Drivers were late” would be written as ?

Solution – cin din fin

Explanation –

“min fin bin gin” means “trains are always late” …………………………….(i)

“gin din cin hin” means “drivers were always punished”………………….(ii)

“bin cin vin rin” means “drivers stopped all trains”…………………………(iii)

“din kin fin vin” means “all passengers were late”……………………………(iv)

From above sentences (i), (ii), (iii), (iv) we conclude that

fin → late

cin → drivers

din → were

So, drivers were late → cin din fin.

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