The term Coding - Decoding primarily relates with massage sent in secret form which can not be understood by others easily. Coding, therefore, means rule or method used to hide the actual meaning of a word or group of words and decoding means the method of making out the actual message that is disguised in coding. Coding – Decoding is two Types. 1. Letter Coding 2. Number Coding.
Letter Coding:
In this, certain letters of alphabet stand for certain other letters of alphabet. For example, LOVE can be coded as MQYI where the first letter L is shifted one place to M, second letter O is shifted two places to Q, third letter V is shifted three places and so on. Hence according to this pattern the code for ANIL will be BPHP.
Number Coding:
In this type, letters are changed by the number of letters in their corresponding alphabetic position. Some important questions are discussed below
Some Models:
* In a certain code language OUTCOME is written as OQWWEQOE. How is REFRACT written in that code?
1) RTGITCET 2) RTGTICET 3) RTGITECT 4) RTGICTET 5) None of these
Ans: 1.
Hint: The first letter is coded as two letters: the first remains unchanged and the second two letters forward as in English alphabet. The second, fourth, fifth and sixth letters are coded as two letters forward while the third letter is coded as three letters forward as in English alphabet. The last letter remains unchanged.
* In a certain code language GEOPHYSICS is written as IOPDHZRJBT. How is ALTIMETERS written in that code?
1) NHULBFSDQT 2) NIUKBFSDQT 3) NHUKCFSDQT 4) NHUKBFSEQT
5) None of these
Ans: 5
Hint: Divide the word into two hales. Now, reverse the order of the letters of the first half and replace odd positioned letters with one letter forward and even-positioned letter with one letter backward as in English alphabet.
For the second half letters, the odd-positioned letters are coded as one letter forward and even-positioned letters are coded as one letter backward as in Englishalphabet.
* In a certain code language BRAKE is written as ASDBJ. How is SOLAR written in that code?
1) RPKBS 2) TPMBS 3) RPKBQ
4) TPKBQ 5) None of these
Ans: 3.
Hint: The odd-positioned letters are coded as one position backward and the evenpositioned letters are ended as one position forward as in English alphabet.
* In a certain code language EMPHASIS is written as NDIOBRJR. How is CREATURE written in that code?
1) SBBDUTSD 2) QBBDTUSD 3) DSDBSTSF
4) SBDBUTDS 5) None of these
Ans: 1.
* In a certain code language BORN is written as APQON and LACK is written as KBBLK. How is GRID written in that code?
1) FQHCD 2) FSHED 3) HSJED
4) FSHCD 5) None of these
Ans: 2.
Hint: B O R N
-1 +1 -1 +1
A P Q O N
L A C K
-1 +1 -1 +1
K B B L K
Similarly,
G R I D
-1 +1 -1 +1
F S H E D
* In a certain code language STREAMLING is written as CGTVUHOJMN. How is PERIODICAL written in that code?
1) PJSFQMNBJE 2) QKTGRMBDJE 3) QKTGRMCEKF
4) PJSFQMBDJE 5) None of these
Ans: 2.
Hint: Split the word STREAMLING into two groups consisting of equal letters. You get STREA and MLING. Now, reverse both the groups. You get AERTS and GNILM. Write each letter of second group two places forward. You get CGTVU. Write each letter of second group one place forward. You get HOJMN. Now join both the groups without changing the order of letters. You get CGTVUHOJMN.
Similarly PERIODICAL is coded as PERIODICAL - OIREPLACID -- QKTGRMBDJE
* In a certain code language OVER is written as PWFSQ and BARE is written as CBSFD. How is OPEN written in that code?
1) PQFOM 2) NODMO 3) PQFOO 4) POFMM 5) None of these
Ans: 1.
Hint: O V E R O P E N
+1 +1 +1 +1 -5 Similarly, +1 +1 +1 +1 -1
P W F S Q P Q F O M
* In a certain code language OMNIPRESENT is written as QJONPTSMDRD. How is CREDIBILITY written in that code?
1) JEFSDCXSHKH 2) JEFSDDXSHKH 3) DSFEJDDXSHKH
4) JEFSDXDSHKH 5) None of these
Ans: 2.
Hint: Split the word OMNIPRESENT in three parts OMNIP, R, and ESENT.
Reverse the order of the letters of the first part. It becomes PINMO. Now write each letter of this part one place forward, i.e PINMO becomes QJONP. Write the letter of the second part two places forward, i.e R becomes T. Again, reverse the order of the letters of the third part, i.e ESENT becomes TNESE. Now write each letter one place backward, i.e TNESE becomes SMDRD. Hence OMNIPRESENT is coded as QJONPTSMDRD. Similarly, CREDIBILITY will be written as JEFSDDXSHKH.
* In a certain code language POETRY is written as QONDSQX and OVER is written as PNUDQ. How is MORE written in that code?
1) NNNQD 2) NLPQD 3) NLNQD 4) LNNQD 5) None of these
Ans: 3.
* In a certain code language MOTHERS is written as OMVGGPU. How is BROUGHT written in that code?
1) CPRTIEV 2) DPQSIFV 3) DPRTIDV 4) DPQTIFV 5) None of these
Ans: 4.
Number Coding:
Some Models:
* If each alphabet is assigned a sequential numerical value in terms of odd numbers on the basis of their position in the English alphabet; viz. A = 1; B = 3; C = 5 and so on. What will be the value of the word DESK?
1) 76 2) 74 3) 64 4) 68 5) None of these
Ans: 2.
Hint: According to the question, the value of all the letters will be: its sequential numerical value as in English alphabet + the no. of letters before it in English alphabet.
Hence D = 4 + 3 = 7, S = 19 + 18 = 37
E = 5 + 4 = 9 , K = 11 + 10 = 21
* If each of the letters in the English alphabet is assigned odd numerical value beginning
A = 1, B = 3 and so on, what will be the total value of the letters of the word 'INDIAN'?
1) 96 2) 89 3) 88 4) 86 5) None of these
Ans: 1.
Hint: INDIAN = 17 + 27 + 7 + 17 + 1 + 27 = 96
* If all consonants starting from B are given sequentially the value of even numbers such as B = 2, C = 4 and so on and all the vowels are given the value of 5 each, then what will be the value of the letters of the 'CUSTOM'?
1) 92 2) 86 3) 82 4) 96 5) None of these
Ans: 4.
* If letters in the word HAEMOPHILIA are arranged in the alphabetical order and each letter is assigned numerical value equal to its serial number from the left in this rearranged order, what is the difference in the total of numerical values of vowel and that of consonants?
1) 8 2) 9 3) 10 4) 7 5) None of these
Ans: 1.
Hint: Arranging the word alphabetically, we get,
A A E H H I I L M O P
1 2 3 4 5 6 7 8 9 10 11
Difference = (4+5+8+9+11) - (1+2+3+6+7+10) = 8
* If letters in the word SHAMEFACED are arranged in the alphabetical order and each letter is assigned numerical value equal to its serial number from the right in this rearranged order, what is the difference in the total of numerical values of vowels and that of consonants?
1) 21 2) 13 3) 9 4) 5 5) None of these
Ans: 4.
* If each alphabet is assigned a sequential numerical value in terms of even numbers on the basis of their position in the English alphabet; viz. A = 2, B = 4, C = 6 and so on, what will be the value of the word ZANDU?
1) 130 2) 122 3) 142 4) 132 5) None of these
Ans: 4.
Hint: Z + A + N + D + U = 52+2+28+8+42 = 132
* If each alphabet is assigned a sequential numerical value in terms of multiples of 3 on the basis of their position in the English alphabet, viz. A= 3, B = 6, C = 9 and so on, what will be the value of the word FEAST?
1) 51 2) 153 3) 157 4) 193 5) None of these
Ans: 2.
* If each alphabet is assigned a sequential numerical value in terms of even numbers on the basis of their position in the English alphabet, viz. A = 2, B = 4, C = 6 and so on, what will be the value of the word LOCATION?
1)180 2) 182 3) 186 4) 178 5) None of these
Ans: 4.
Hint: Here the value of each letter = its place value as in English alphabet x 2.
Hence LOCATION = 2 x (12+15+3+1+20+9+15+14) = 178
* If letters in the word ULTRAVIOLET are rearranged in the alphabetical order and, each letter is assigned numerical value equal to its serial number as in the English alphabet,what is the difference between the sum of odd-positioned no's, and that of even-positioned no's?
1) 11 2) 7 3) 15 4) 9 5) None of these
Ans: 4.
Hint: Arranging the letters as in English alphabet, we get
A E I L L O R T T U V
1 5 9 12 12 15 18 20 20 21 22
Difference = (1+9+12+18+20+22) - (5+12+15+20+21) = 9
* If GIVE is coded as 5137 and BAT is coded as 924, how is GATE coded?
1) 5427 2) 5724 3) 5247 4) 2547 5) None of these
Ans: 3.
Hint: The alphabets are coded as shown
G I V E B A T
5 1 3 7 9 2 4
i.e G as 5, A as 2, T as 4, and E as 7.
So, GATE is coded as 5247.
