Title 09-Coding _ Decoding.pdf ✅

FOR EDITABLE MS WORD +919206306398 Coding & Decoding 60 CODING & DECODING 9 CHAPTER The term Coding-Decoding primarily relates with message 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. Category I In this category of questions, a word is coded by simplychanging the order of letters of the word. EXAMPLES  Ex.1 In a code language if TRAINS is coded as RTIASN, how PISTOL will be coded in the same language ? (A) SITLOP (B) IPSTLO (C) SIPTLO (D) IPTSLO Sol. If we compare the basic word {TRAINS} with the coded word {RTIASN}, we would see that the letters used in the word are same as in the basic word but their order of placement has been changed. Letter T at first position of basic word has been placed at second position in the coded word & letter R at second position has been placed in the first position. It means that in this question, letters of the basic word have been interchanged i.e., first letter with second, third with the fourth and so on. And thus we get the coded word. In this code language word, PISTOL will be coded as IPTSLO. Hence, option (D) is our answer. Category II In this category of questions, letters of a word are substituted for either a new letter or a numeric. And the same substitution helps to find out the coding of the word in questions. This substitution of letters may either be direct or in a jumbled up fashion. (A) Direct Substitution Ex.2 In a code language if SUGAR is coded as PKLTN and TEA is coded as QGT, how would you code GREAT in the same code language ? (A) ENGTP (B) LNGTK (C) LNGTQ (D) LNGQT Sol. Here we see that S is substituted for P, U for K, G for L, A for T & R for N. And in the word TEA. T is substituted for Q, E for G and A for T. Now we find that coding for letter A in SUGAR is T and coding for letter A in TEA is also T. This implies that substitution of letter in coded word takes place in the same order as in basic word. In simple words, in the word SUGAR letter S in the basic word has been substituted for a new letter and coded at first place in the coded word, U at the second place, G at the third place and so on. When letters of a word are substituted for the new letters and are placed in the coded word at the same position as in the basic word then this method of substitution is called direct substituion. Therefore, code for GREAT will be LNGTQ. Hence, option (C) will be our answer. Ex.3 In a code language if TEARS is coded as VWXYZ and MAN is coded as 123 then how would you code RESENTMENT in that language ? SUGAR PKLTN Basic Word Coded Word TEA QGT Basic Word Coded Word
FOR EDITABLE MS WORD +919206306398 Coding & Decoding 61 (A) YWZW3V1W3Y (B) YWZ3WV1W3Y (C) YWZW3V1WY3 (D) YWZW3V1W3V Sol. This questions is of direct substitution method. Letters of the basic words are substituted as under. Therefore, the coding for the word RESENTMENT will be YWZW3V1W3V. Hence, option (D) is our answer. Ex.4 If TEARS is coded as VWXYZ, then how would you code BEAS in that language ? (A) YWXZ (B) VWXZ (C) MWXZ (D) WVZY Sol. Using the same coding pattern for BEAS, we get W for E, X for A & Z for S but code for B can not be determined as it is absent in the basic word. Now we shall take the help of options. In option (A) we get W, X, Z for E, A & S respectively which is correct but coding for B can not be Y as it is the coe for R. Likewise in option (B). V can not be coded for B as it is the code for T. In option (C) we see that code for B is M which seems to be correct as it has not been used as a code for any of the letters in basic word. Hence, code for BEAS would be MWXZ. Therefore option (C) is our answer. (B) Substitution in mixed up fashion Rule applied in this type of questions follows the same pattern as used in type (A) – Direct substitution but with slight modification. Here also in this type each letter of basic word is substituted for a new letter but it may not necessarily be placed in the same position in coded word as it occupies in the basic word. In simple words, it implies that coded letter at first position in basic word does not necessarily occupy the first position in the coded word. It can be placed at any place in the coded word. Ex.5 In a code language, if BEAT is coded as 5642 and SWEET is coded as 66912, how would you code TEASE ? (A) 96162 (B) 56264 (C) 96625 (D) 55296 Sol. Coding pattern used in the above question substitution for the letters has not been used directly. Code for E seems to be 6 in BEAT whereas it carries code 9 and 1 in the word SWEET which apparently appears to be incorrect because in substitution method same letter carries same code even if it appears in different word. Now in word SWEET letter E appears twice and in its coding numeric 6 appears twice. Thus it is confirmed that code for E is 6. It may be concluded from the coding pattern used here that letters of the words BEAT and SWEET have been substituted for numeric in jumbled up form. Word BEAT and SWEET share common letters E and T and their coding share common numeric 6 and 2. Therefore, E is coded as 6 and T is coded as 2. It means that the code for TEASE will definitely have 6 6 & 2 for E, E and T. Code for A and S has yet to be found out. Now from word BEAT and SWEET again, we see that code for A in word BEAT should be either 5 or 4 (leaving 6 & 2 for E and T). Similarily, code for S should be either 9 or 1 (leaving 6 & 2 for E and T). We shall not take the help of options to answer the code for TEASE. (A) It cannot be the code for TEASE as code for A (5 or 4) is not available. (B) It cannot be the code for TEASE as code for S (9 or 1) is not available. (C) It may be the code for TEASE as besides 662 code for EE and T, we get 5 probable code for A and 9 probable code for S. Hence, option (C) is our answer. Category III Basic Word : T E A R S Coded Word : V W X Y Z Basic Word : M A N Coded Word : 1 2 3 Basic Word : T E A R S Coded Word : V W X Y Z BEAT 5 6 4 2 Basic Word Coded Word S W E E T 6 6 9 1 2 Basic Word Coded Word
FOR EDITABLE MS WORD +919206306398 Coding & Decoding 62 In this category, rule of coding is of entirely different type from what has been discussed so far in category I and II. IN this type, word is coded, replacing each letter of the word by a new word from the alphabets (A ...... Z) on the basis of a particular method. It has been explained in the following examples - Ex.6 If TEMPLE is coded as VHQURL, how would you code CHURCH ? (A) EKYWIO (B) EKUWIO (C) EKYWIN (D) EKYWJO Sol. Code for T is V, for E it is H, for M it is Q. It may be noticed from here that letters of TEMPLE have been replaced by new letters from the alphabets. There is a gap of one letter between T and V, gap of two letters between E and H, gap of three letters between M & Q and so on in the alphabets. Therefore, coding for CHURCH is C H U R C H +1 +2 +3 +4 +5 +6 E K Y W I O Hence (A) is our answer. Ex.7 If TEMPLE is coded as VHQNIA, how would you code CHURCH ? (A) EKYWI (B) EKYQZD (C) EKYPZD (D) EKYQWD Sol. Coding for TEMPLE is T E M P L E +1 +2 +3 –1 –2 –3 V H Q N I A Here, the first half of the letters of the word TEMPLE have been replaced with new letters from the alphabets with a gap of 1, 2 & 3 letters respectively in forward direction, and second half of the letters of the word have been replaced by new letters from the alphabets with a gap of 1, 2 and 3 in backward direction. Hence, code for word CHURCH would be EKYPZD. Hence, (C) is our answer. Directions : (Ex. 8 to 10) The number in each question below is to be codified in the following code : Digit 7 2 1 5 3 9 8 6 4 Letter W L M S I N D J B Ex.8 184632 (A) MDJBSI (B) MDJBIL (C) MDJBWL (D) MDBJIL Sol. As given 1 is coded as M, 8 as D, 4 as B, 6 as J, 3 as I and 2 as L. So, 184632 is coded as MDBJIL. Ex.9 879341 (A) DWNIBS (B) DWNBIM (C) DWNIBM (D) NDWBIM Sol. As given 8 is coded as D, 7 as W, 9 as N, 3 as I, 4 as B and 1 as M. So, 879341 is coded as DWNIBM. Ex.10 64928 (A) JBNLD (B) JBLND (C) BJNLD (D) DBNLS Sol. As given , 6 is coded as J, 4 as B, 9 as N, 2 as L and 8 as D. So, 64928 is coded as JBNLD. Ex.11 In a certain code, 15789 is written as AXBTC, 2346 is written as MPDU. How is 23549 written in that code ? (A) MPXDT (B) MPADC (C) MPXCD (D) MPXDC Sol. The numbers are coded as shown : 1 5 7 8 9 2 3 4 6 A X B T C M P D U i.e., 2 as M, 3 as P, 5 as X, 4 as D and 9 as C. So, 23549 is coded as MPXDC. Ex.12 In a certain code, 15789 is written as XTZAL and 2346 is written as NPSU. How is 23549 written in that code ? (A) NPTUL (B) PNTSL (C) NPTSL (D) NBTSL Sol. The numbers are coded as shown : 1 5 7 8 9 2 3 4 6 X T Z A L N P S U i.e., 2 as N, 3 as P, 5 as T, 4 as S and 9 as L. So, 23549 is coded as NPTSL. Ex.13 In a certain code, 33946 is coded as PPOAL and 1987 is coded as ROSE. How is 94678 coded in that code ? (A) ROSEP (B) OALES Basic Word Coded Word TE MPLE V HQ UR L
FOR EDITABLE MS WORD +919206306398 Coding & Decoding 63 (C) POALE (D) OSEPL Sol. The numbers are coded as shown : 3 9 4 6 1 8 7 P O A L R S E i.e., 9 as O, 4 as A, 6 as L, 7 as E and 8 as S. So, 94678 is coded as OALES. Ex.14 If in a certain language, 943 is coded as BED and 12448 is coded as SWEET, how is 492311 coded in that language ? (A) EDSWBS (B) TSWBDD (C) DSWTEE (D) EBWDSS Sol. The number are coded as shown : 9 4 3 1 2 8 B E D S W T i.e., 4 as E, 9 as B, 2 as W, 3 as D and 1 as S, So, 492311 is coded as EBWDSS. Ex.15 If MOBILITY is coded as 46293927, then EXAMINATION is coded as (A) 45038401854 (B) 56149512965 (C) 57159413955 (D) 67250623076 Sol. Let A=1,B=2,C=3,..., X = 24, Y =25,Z=26. Then, M = 13 = 1 + 3 = 4; O = 15 = 1 + 5 = 6; L = 12 = 1 + 2 = 3; T = 20 = 2 + 0 = 2; Y = 25 = 2 + 5 = 7. So, MOBILITY = 46293927. Similarly, EXAMINATION = 56149512965. Ex.16 If MASTER is coded as 411259   then POWDER will be coded as (A) 7 65439  (B) 765439  (C) 7 65459  (D) 765549  Sol. Let A = 1, B = 2, C = 3, ..., Z = 26. Now, M = 13 = 4 (remainder obtained after dividing by 9); S = 19 = 1 (remainder obtained after dividing by 9 twice); T = 20 = 2 (remainder obtained after dividing by 9 twice); R = 18 = 9 (remainder obtained after dividing by 9). So, MASTER = . 411259  Similarly, POWDER = 7 65459  . Ex.17 In a certain code, 15789 is written as EGKPT and 2346 is written in ALUR. How is 23549 written in that code ? (A) ALEUT (B) ALGTU (C) ALGUT (D) ALGRT Sol. In the given codes, the numbers are coded as shown : 1 5 7 8 9 2 3 4 6 E G K P T A L U R i.e., 2 as A, 3 as L, 5 as G, 4 as U and 9 as T. so, 23549 is coded as ALGUT. Ex.18 In a certain code, a number 13479 is written as AQFJL and 5268 is written as DMPN. How is 396824 written in that code ? (A) QLPNKJ (B) QLPNMF (C) QLPMNF (D) QLPNDF Sol. In the given codes, the numbers are coded as shown : 1 3 4 7 9 5 2 6 8 A Q F J L D M P N i.e., 3 as Q, 9 as L, 6 as P, 8 as N, 2 as M and 4 as F. So, 396824 is coded as QLPNMF. EXERCISE