Coding-Decoding Topic : Reasoning

Coding-Decoding (for Bank PO/Clerk/SSC/Railway)

A code is a system of signals. Therefore, coding is a method of transmitting messages between the sender and receiver without a third person understanding it. The Coding and Decoding test is set up to judge the candidate’s ability to decipher the law that codes a particular message and break the code to reveal the message.

LETTER TO LETTER CODING:

A particular letter stands for another letter in letter coding.

e.g: If COURSE is coded as FRXUVH, how is RACE coded in that code?

(1) HFDU               (2) UCFH               (3) UDFH               (4) UDHF              (5) UDFG
In the given code, each letter is moved three steps forward than the corresponding letter in the word. So ‘R’ is coded as U, A as D, C as F, E as H. answer is (3). 

NUMBER CODING (Letter to Number/Number to Letter)

In this section either numerical code values are assigned to a word or alphabetical code values are assigned to numbers. The candidate is required to analyse the code as per directions.
English alphabets and their corresponding number values help the candidate to increase the performance in this area. The position of the letter in the English Alphabet is considered to be the value of the alphabet in questions on letter series. Also, when we are counting from A to Z, we again start with A, i.e. we treat the letters as being cyclic order. Alphabets in natural series are:

Case I: When numerical values are assigned to words.

e.g: If in a certain code ROPE is coded as 6821, CHAIR is coded as 73456 what will be the code for CRAPE?

(1)73456 (2) 76421 (3) 77246 (4) 77123 (5) None of these

Clearly, in the given code, the alphabets are coded as follows.

R O P  E  C  H  A  I
6  8  2  1   7  3  4  5

So CRAPE is coded as 76421 and the answer is (2)

Case II: When alphabetical code values are assigned to the numbers.

e.g: In a certain code 3456 is coded as ROPE. 15546 is coded as APPLE. Then how is 54613 coded?

(1) RPPEO (2) ROPEA (3) POEAR (4) PAREO (5) None of these

Clearly in the given figures, the numbers are coded as follows:
3  4  5 6 1  4
R O P E A  L
So 54613 is coded as POEAR and the answer is (3)
The Word EJOTY is very helpful in finding the position of the alphabet as:
For example, if we want to find the position (according to English Dictionary) of the alphabet ‘K’, then as we know that ‘J’ is 10, so ‘K’ is 10 + 1 = 11.
We can also find the position of an alphabet from the end/Last (from opposite side) by subtracting its value from 27 (See Fig-1). For example, find the position of M from the end? (Questions also asked in this way- Position from the last)
Solution: From Fig-1 Sum is 27 and Current Position of M according to English dictionary is 13. Now we have to find opposite side position of M i.e. 27 – 13 = 14.
Note: For finding position of an alphabet from the last/opposite/end always remembers there are total 26+1=27 alphabets.
The pattern below is very useful to find many types of question in Alphabet Series when we write the last 13 alphabets in front of the first 13 alphabets of the English:
SUBSTITUTION TYPES:
Substitution In substitution type of questions, some particular objects are assigned code names. Then a question is asked that is to be answered in the code language.

For example, if orange is called butter, butter is called soap, soap is called ink, ink is called honey and honey is called orange, which of the following is used for washing clothes?

a) Honey       b) Butter       c) Orange       d) Soap       e) Ink                                          Ans: e

The questions on coding and decoding are basically five types as given below.
I. LETTER TO LETTER:
1. In a certain code ‘SHIMLA’ is written as ‘RGHLKZ, how will PATNA be coded then?
a) OZTMZ                 b) OZSMZ                    c) QBUMB                   d) OZTZM
Sol: Each letter is coded as the letter previous to it, i.e. S = R, H = G, I = H, M = L, L = K, A = Z. PATNA will become OZSMZ. Hence the answer is (b).
II. LETTER TO NUMBER:
2. If LODES is coded as 46321, how will you code the word DOES?
a) 1234                        b) 4321                        c) 3621                        d) 3261
Sol:      Here, you will observe that all the letters of DOES are included in the letters of LODES, for which you have the code D = 3, O = 6, E = 2, S = 1. Therefore DOES = 3621. So, the answer is (d).
III. NUMBER TO LETTER:
2. If DELHI is coded as 73541 and CALCUTTA as 82589662, how can CALICUT be coded?
Options:
A. 5279431       B. 5978213       C. 8251896       D. 8543691
Sol:   in CALICUT, C is coded as 8, A as 2, L as 5, I as 1, U as 9   and T as 6. Thus Code for CALICUT: 8251896. So, the answer is (c)
IV. MISCALLANEOUS TYPES:
4. In a certain code ‘415’ means ‘milk is hot’; ‘18’ means ‘hot soup’; and ‘895’ means ‘soup is tasty’. What number will indicate the word ‘tasty’?
a) 9                              b) 8                              c) 5                              d) 4
Sol:   The code for ‘hot’ is 1. So, the code of ‘soup’ is 8. Now the code of ‘is’ is 5. Hence we can say that the code of ‘tasty’ is 9. So, the answer is (a)     
V. SUBSTITUTION TYPES:

 

5. If air is called green, green is called blue, blue is called sky, sky is called yellow, yellow is called water and water is called pink, then what is the color of clear sky?

Options:

a) Blue       b) Sky       c) Yellow       d) Water       e) Pink                                               Ans: Sky

Exercise

1. In a code language, A is written as B, B is written as C, C is written as D and so on, then how will SMART be written in that code language ?
a) TLBSU              b) SHBSU             c) TNBSU              d) SNBRU                             Ans: c
The letters are coded by moving them 1 step forward.
2. In a certain code, RIPPLE is written as 613382 and LIFE is written as 8192. How is PILLER written in that code?
a) 318826             b) 776655             c) 786543              d) 156724                             Ans: a
3. In a certain code, 'bi nie pie' means 'some good jokes’ ;  'nie bat lik' means 'some real stories' ; and 'pie lik tol' means 'many good stories'. Which word in that code means ‘jokes’?


a) bi       b) nie       c) pie       d) Can’t be determined       e) None of these               Ans: b

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