General Inteligence for SSC Exams


1.      Coding – Decoding:


A system of signals is called a code. Coding is nothing but a method of transmitting a message between the sender and the receiver which third person cannot know it. In this type of questions some words/group of letters/numbers and their forms are given and you are required to find out the rule of coding, so that you can either encode or decode another word or another group of letters is similar fashion.

The various types are:

  1. Letter coding
  2. Number coding
  3. Matrix coding
  4. Substitution
  5. Mixed letter coding
  6. Mixed number coding.


Letter coding:


v      Positions of alphabets in a word are replaced by other alphabets according to certain rule.

v      Find the common rule.

v      Coding the given information using the above rule.


Consider a – 1, b – 2, c -3………………z – 26.


  1. In a certain code language 'WORLD' is coded as 'XPSME' how is 'SPECIAL' coded in that language?


Ans:     TQFDJBM



      Clearly, each letter in the word 'WORLD' is moved one step forward to obtain the corresponding letter of the code.


      W         O         R          L          D

      X          P          S          M         E


      So, in SPECIAL, S will be coded as T, P as Q, E as F, C as D, I as J, A as B and L as M. Thus the code becomes TQFDJBM.



  1. If 'CAT' is coded as 'BZS' then how is 'MAT' coded?


Ans:     LZS



      Each letter in the word CAT is moved one step backward to obtain the corresponding letter of the code.


      C          A          T

      B          Z          S


      Thus, in MAT, M will be coded as L, A as Z and T as S.

      Thus, the code becomes 'LZS'.



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