• Coding-Decoding

    A CODE is a signal. Coding has always been used to transmit messages in such a way that they are not ordinarily understood, unless these are decoded. These messages can only be understood by the receiver if he has the ‘code key’ to decipher it. Thus, the “CODING DECODING” test is given to judge the candidate’s ability to decipher the ‘rule applied in coding’. The coding is generally based on alphabets and some times numerals are also used to code the messages. Though, all the methods of coding can not be identified but still the major formats of coding are as under:

    Coding and Decoding can be classified into following types:-

    Type – 1 Reversal of Alphabets

    The alphabets of the word are reversed in such a way that the last letter is the code of first letter. It is the easy format of the coding and it is the first thing to be looked when we look at coding.

    Ex. 1 In a certain code language BREAKDOWN is written as NWODKAERB. How will TRIANGLES be written in that code language?

    (1) AIRTGNSEL      (2) SELGWTRIA       (3) AIRTNSELG       (4) SELGNAIRT       (5) None of these

    Sol. (4) The order of letters has been reversed in the code. Following the coding given above, TRIANGLES will be Coded as SELGNAIRT

    Type – 2 Opposite Letters

    The second type of coding is by ‘use of opposite letters’. We can understand this type from the rule of 27, which inform us how to find out the opposite letters of the alphabet. Knowing the position value of each alphabet and using the second rule of 27, we can easily find out if the word is coded in ‘opposite letters’. Here A will be coded as Z. Therefore B will be coded as Y and C will be coded as X.

    Ex.2 In a certain code ORDER is written as LIWVI. How is SUBSTITUTION written in that code?

    1) HFYHGRGFGRLM       2) HFHYGRGRLM       3) HFYHGRGRML       4) HFYHGRHGGQLM       5) None of these

    Sol (1) A perusal of the word ORDER and its coded word LIWVI and knowledge of second rule of 27 shows that L is opposite letter of O, I is opposite of R, W is opposite of R and so on. It means that the coded word contains all the opposite letters. Keeping this in view, we know that SUBSTITUTION will be coded as HFYHGRGFGRLM.

    Type – 3 Increment / Decrement

    In this type of questions either preceding or following letter stands as the code letter for each of the letters of the given word. For example,

    Ex. 3) In a certain code language, ‘TEMPORARY’ is written as ‘SFLQOQBQZ. How would ‘WONDERFUL’ be written in the same code?

    (1) VPMEFQGTM       (2) VPMEESGTM       (3) XPMEEQGTM       (4) VPMEESEVK       (5) None of these


    We observe that letters are alternatively moved one place forward and one place backwards and the letter in the middle of the given word is not changed. Based on this observation we coded the word ‘WONDERFUL’ as ‘VPMEEQGTM’. Therefore the ans. is (5).

    Type – 4 Jumbling of words

    In this type of coding, the letters of the given word are moved in a particular way and for the purpose of decoding, the same format is required to be followed. In jumbling also a series has to be there.

    Ex. 4) In a certain code language AUTHORITY is written as YTUROHTIA. How will DESIGNATE be written in that code language?

    (1) ESENGATDI      (2) ESEGNITAD      (3) ESENGITAD      (4) ESNEIGTDA      (5) None of these

    Sol. (3) In the coded form the first and the last (ninth) letters have been interchanged so as the second and third, the fourth and the sixth and the seventh and the eight letters while middle letters (i.e. fifth) is left intact. Thus,

    Type – 5 Using additional alphabets

    In this type of problems, two letters are used for each letter of the word. For example: letters O & Q are used for the corresponding letter P in the given word and letters K and M are used for the letter L. In this way, all the letters are coded by using preceding and succeeding letter for every letter used in the word.

    Ex.5 In a certain code DELHI is written as CEDFKMGIHJ. How is KOLKATTA written in that code?


    Sol. (1) We can observe that there are five letters in the word Delhi and it is coded in ten letters. It means two letters has been used for every one letter used in the word ‘Delhi’. It can also be easily observed that for the letter D two letter C and E have been used. Similarly for the letter E the letters used are D and F. From this, we can conclude that preceding & succeeding letters have used to code each letter. Following this pattern of coding we can code KOLKATTA as JLNPKMJLZBSUSUZB.

    Type – 6 Reducing two alphabets to one.

    In this type of reasoning it is observed that place value of two adjusting letters are added and letter representing the new place value is the code for the given word.

    Caution:We have to careful when the sum of place value of two letters exceeds 26. Two variants are possible in such a case:-

    1. Let the sum of place value of two alphabets is 33, the coded word can be 33-26=7 i.e. ‘G’.
    2. The figure 33 can be added up again as 3+3=6 and the alphabet at place value 6 is ‘F’.

    In case, there is no reference in the example given to us, then we will have to observe the options given to us.

    Ex 6) If GAMBLE is coded as HOQ, how is DOCTOR coded in that language?

    1) SXG       2) SWH       3) SWF       4) SWG       5) None of these

    Sol. (4) The place value of G is 7 and the place value of A is 1 then total of their place value is 8 which is presented by H in the alphabet series. Similarly, place value of M is 13 and B is 2 then the sum is 15 which is represented by O. The place value of L and E is 12 & 5 respectively and their sum total is 17 which is represented by Q in the alphabet series. So the coded word is HOQ. Similarly we can code DOCTOR as under:

    Type – 7 Adding up place value

    It is some time observed that the given word is coded in numeric form. Generally the place values of the letters used in the word are added up and the resultant sum is the coded form of the given word. If the word CAT is coded as 24 because the place value of all the letters are added up.

    Ex 7) If MADRAS is coded as 56, how is CALCUTTA coded in that language?

    1) 80       2) 81       3) 82       4) 76       5) None of these

    Type – 8 Code consisting of a group of words

    In this type of questions a group of words or a sentence as a whole is coded and on the basis of common words you are required to ascertain the code for each word.

    Ex 8) In a certain code : ‘ing ping sing’ means ‘how are you’ , ‘sing ring ding’ means ‘what about you’ and ‘ding fing ching’ means ‘what to do’ ,then how is ‘do’ written in this code language?

    (1) ing       (2) fing       (3) ching       (4) data inadequate       (5) None of these

    Sol: In the first and second sentence, ‘you’ is common while in the coded statement, the common word is ‘sing’. It means that sing is the code for you. Similarly, in the second and third sentence, the common word is ‘what’ and ‘ding’ respectively. From it, we can conclude that the coding for ‘what’ is ‘ding’. But for the ‘do’ we cannot assign the code because it can be coded either as’ fing’ or ‘ching’. Our answer to the question here should be ‘data inadequate’ or option number (4).

    Type – 9 Renaming

    In this type of questions, certain words are assigned different names and you are required to ascertain the code for a particular word.

    Ex. 9) If ‘green’ is called ‘white’, ‘white’ is called ‘yellow’, ‘yellow’ is called ‘blue’, ‘blue’ is called ‘pink’ and ‘pink’ is called ‘black’, then what is the colour of milk?

    (1) green       (2) blue       (3) pink       (4) yellow       (5) None of these

    Sol. (4) The colour of milk is white. But the code of white is yellow so the answer is yellow.

    Type – 10 Given two words & Two find code for third

    In this type, we have three categories which are defined as follows:-

    Alphabets to Alphabets

    Some times we are given two or more words along with their coding & we don’t observe any direct relationship with regard to their place value in the alphabet. So we look for other formats of coding. In the example given below, we know that NUMBER is coded as EPRSAY and SQUARE is coded as NGPVYA. We observe that U is coded as P in both the words and E is coded as A. From this we conclude that letters used in the code correspond to the letters in the coded word. This can be observed by the example given below:

    Ex. 10.1) If the word ‘NUMBER’ is coded as ‘EPRSAY’ and ‘SQUARE’ is coded as ‘NGPVYA’ then how do we code ‘MEMBER’.

    a) RARSYA      b) RRASYA       c) RARSAY       d) SARSAY       e) None of these

    Sol. (1) When we observe the coded word and the corresponding, code it is observed that the coding is neither in the form of opposite letters; nor correspond place value in the alphabet. The only thing common between the two coded words are the letters U and E and these letters are coded as P and A respectively in both the given words. Their placement in the code corresponds to their position in the coded words. Based on this information, we draw the table as shown below and find the code for each letter:

    If we observe from the table above table, M is coded as R, E is coded as A, B is coded as S. So the answer is RARSAY.

    Answer - 3

    Numerals to Alphabets

    Ex 10.2) If 134796 is coded as AQFJLP and 5268 is coded as DMPN then How 396824 is coded?

    1) QLPNMF       2) QJPNMF       3) QLPMNF       4) QPNMLF       5) None of these

    Sol. (1) We observed that there is no direct relationship with the coded word and the relative code. But it is observed that 6 is coded as P in both the words. Its position in the code is directly relative to ‘6’ of the coded word. We draw the table as given below:

    We come to the conclusion that 1 is coded as A, 3 is coded as Q, 4 is coded as F, 7 is coded as J, 9 is coded as L and 6 is coded as P, Also 5 is coded as D, 2 is coded as M, 6 is coded as P and 8 is coded as N. Because 3 is coded as Q. 9 is coded as L, 6 is coded as P, 8 is coded as N, 2 is coded as M, 4 is coded as F, therefore the answer is ‘QLPNMF’

    Numerals to Numerals

    Ex 10.3) If in a certain code 24685 is coded as 33776, then how 35791 will be coded as:

    1) 44882       2) 46882       3) 46683       4) 36683       5) None of these

    Alphabets to Symbols

    In this type of questions each letter of a word is coded as symbol or digit and on the basis of that coding pattern you are required to ascertain the code of the given word.

    Ex 10.4) In a certain code, ‘SPRING’ is written as ‘#2%@4=’ and ‘GONE’ is written as ‘=74(c). How would SIGN be written in the same code?

    (1) #@4 =       (2) 2@ = 4       (3) #@ = 4       (4) #% = 4       (5) None of these

    Alphabets to Numerals

    Ex 10.5) In a certain code language BREAK is written as 51642 and KITE is written as 2796. How will RATE be written in that code language?

    (1) 1494       (2) 1496       (3) 1495       (4) 1492       (5) None of these

    Type – 11 Exception

    Ex. 11) Study the following information carefully and answer the questions given below:The digits from 0 to 9 are coded as shown below with the exceptions that follow:?

    Exceptions: 1. If number begins and ends with an odd digit (non-zero), then both the first and last digits are to be coded as $.

    2. If a number begins and ends with an even digit (including zero), then both the first and last digits are to be coded as #.

    11.1) What will be the code for 314926?

    (1) MPBDHA      (2) MPBTND       (3) MPBTNA       (4) $PBTN$       (5) None of these

    Type¬ – 12 Matrix form

    In each of the following questions, two rows of numbers are given, the resulted number in each row is to be worked out separately, based on following rules & question below the row of the numbers are to be answered. The operations of numbers are progressing from left to right.

    The rules which have to be followed for the following questions.

    • If odd no is followed by composite no then add both the numbers.
    • If even no is followed by odd no then add both the numbers.
    • If even number is followed by perfect square then subtract even no from perfect square.
    • If odd no is followed by prime odd no then odd no is divided by prime no.
    • If odd no is followed by even no then Subtract even no from odd number.

    Type – 13 Underline letters

    In each question, there is a word written in a capital letter, with one letter under lined for each letter in that word. There is a code written in small letters. The code is denoted by 1, 2, 3, 4 or 5 not in same order. You have to find-out exact code for the underlined letter in the word. The no of code is ans.