Coding Decoding

For this topic, we just have to learn Alphabets. Yeah, we all have learned this in our nursery or pre-nursery classes, but we just have to look into those points which we missed out earlier or some points which were not as memorable before as “2 × 2 = 4” was.

What Coding-Decoding is all about?

Coding-decoding is a way of transmitting data between sender and the receiver in an encrypted manner i.e. no person other than actual receiver is in possession to read that information/message/data.
Before transmission, the data is encoded and sent through any medium. When it is received, it is decoded in order to obtain the original data by the receiver. This prevents data from getting leaked or altered in the process of transmission. Thus, helps in maintaining authenticity and privacy!
There are basically four types of questions, which are asked from this topic in Reasoning section of SSC CGL (Tier I) exam.

Types of questions asked are as follows:

1. Letter coding
2. Substitution
3. Mixed letter coding
4. Mixed number coding

Coding is a secretive language which is used to change the representation of the actual term/word/value. The coded language can be framed by

1. Moving the letters one or more steps forward or backward

2. Substituting numbers for letters and vice-versa

3. Writing the letters of the given word in reverse order in part or in whole

4. Replacing the letters in their natural series by the same positioned letters in their reverse series.

Above mentioned are the all ways that can be used in coding questions. Basically in this question we deal with alphabet (26 letters) and everyone knows it very well.

Still you won’t remember the exact position of any random letter say, position of M starting from A and then starting from Z and coding is the game of same. Here you will have to learn each letter position without writing systematically alphabet every time and only practice will help you in out.

For example, if I ask you what comes after the letter R? You can easily say S. But If I ask you that starting from A as 1, P will be at which position? Can you suddenly answer it? I guess, many of you, not. 

So, for this topic, first, we will learn the position of alphabets.

Alphabet in natural series are:

Example of coding:

1. If Face is coded as GBDF, then BADE will be coded as:

A. CBEF            B. CEBF            C. CFBE            D. CBFE           E. CBEA

Solution. Option A

In this type of questions, firstly we have to read complete question then understand the coding pattern in it and then apply same coding pattern with given question word for choosing appropriate answer from the given 5 options.

Here the word is coded by moving the letters one step forward

 F + 1 = G

 A + 1 = B

 C + 1 = D

  E + 1 = F

Similarly,

B + 1 = C

A + 1 = B

D + 1 = E

E + 1 = F

So, our answer will be CBEF which is option A. 

Direction (1-5): Study the following information carefully and answer the questions given below.
In a certain coding language,
“Study Good Kid Space” is written as “915 621 876 579”
“Student Cute Funny Good” is written as “715 621 493 875”
“Carefully Kid Funny” is written as “493 525 915”
“People Study Kid Ground” is written as “349 579 281 915”

1) What is the code of “Good”?
A.876 B.875 C.579 D.621 E.None of these

2) What is the sum of digits of the code of “People”?
A.16 B.21 C.11 D.15 E.Can’t be determined

3) Which of the following word is coded as “915”?
A.Study B.Kid C.Funny D.Ground E.None of these

4) What is the code for “Cute And Funny Kid”, if the code for “Student” is “875”?
A.915 525 715 281 B.715 493 812 915 C.525 621 812 493 D.493 915 715 621 E.812 915 621 493

5) What is the square of the largest digit of the code of “Space”?
A.81 B.36 C.64 D.49 E. None of these

Solution:

1) Answer: D 2) Answer: E 3) Answer: B 4) Answer: B 5) Answer: C

This type of questions will be asked in coding where you have to follow the same pattern of question cord (word). Now we will discuss about Decoding.

Decoding is the reverse of coding. Here the code needs to be deciphered with the help of given words. We use reverse series of alphabet in deciding.

Alphabet in reverse series are:

Note: On reaching Z, the series restarts from A and on reaching A, it restarts from Z.

Example of Decoding:

2. If ZXV stands for ACE; what will YZW stand for?

A. ABD             B. EAC             C. SAD             D. BAD             E. DAD

Solution.  Option D

In decoding we go reverse from Z to A and series restarts on reaching Z from A. We will use this same during solving the question.

The letters of the word ACE are deciphered by decoding ZXV. The letters are decoded by substituting their represented letters in the natural order. (i. e., Z is 1st in the reverse series and A is 1st in natural series).

Z = A (1st position in reverse and natural series respectively)

X = C (3rd position)

V = E (5th position)

Similarly,

Y       Z       W    (letters in reverse series)

B       A       D     (letters in natural series)

2nd   1st   4th   (Position of letters)

Hence, our answer is option D (BAD)

3. In a certain code ‘ra mei ket’ means ‘he is rich’, ‘rui pha jeu’ means ‘run for money’, and ‘pha rui ket’ means ‘money for rich’. Which of the following is the code for ‘rich’?

A. ra                B. pha             C. ket               D. jeu              E. ret

Solution. Option C

According to question:

Code                                             Sentence

1. ra mei ket                                he is rich

2. rui pha jeu                               run for money

3. pha rui ket                               money for rich

After comparing codes and sentences 1 and 3, it is clear that word ‘rich’ is common and so the code of rich is ‘ket’. Hence option C is correct answer here.

4. 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     

E.   None of these

Solution. Option B

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

According to given codes we have a particular letter of a digit 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 that is option B. 

Directions (5-8): Study the following information carefully and answer the given questions.

In a certain code language,

‘fire the deal burn’ is written as ‘pan cha ga mo’,

‘burn are pick stick’ is written as ‘ta ha cum pan’

‘fire the devil burn’ is written as ‘ga cha she pan’

‘pick stick you’ is written as ‘ha cum va’.

 5. What is the code for ‘devil’?

A. She              B. Cha             C. ha                D. pan             E. None of these

Solution.  Option A

After reading information carefully we are able to see it clearly in 3 line there is word devil used at 3rd position and according to that line/coded statement devil is coded as she. So, our answer is ‘she’ which is option A here. 

6. Which of the following can be the code for ‘you devil deal’?

A. Va mo cha               B. Cha ga mo               C. Mo ga va                 D. Either (a) and (c)

E. None of these

Solution.  Option E

According to question, the code for you is va by fourth sentence 3rd word, the code of devil is she by third sentence 3rd word and the code for deal is ga by first sentence third word. So, the code for ‘you devil deal’ is ‘va she ga’ and this ain’t there in any option. Hence, our answer is option E (none of these). 

7. ‘cum’ is the code for?

A. Pick             B. Are              C. Either ‘pick’ or ‘stick’           D. Burn            E. None of these

Solution. Option C

As ‘cum’ is used for ‘pick’ in second sentence and then again ‘cum’ is used for ‘stick’ in fourth sentence. So, it can be either for ‘pick’ or ‘stick’.

 8. Which of the following is the code for ‘the’?

A. Che             B. Cha             C. Pan              D. Cum            E. Mo

Solution. Option B

After comparing codes and sentences 1 and 3, it is clear that word “the” is coded “cha” here. So option B ‘cha’ is correct.

So, after learning this, you can easily tell that P comes at which position (i.e. 16). Or what comes after 3 positions of O (i.e. R) 

[Note: 1. These are the positions assigned to the alphabets when A is appointed as 1. But in some scenarios, A can be appointed as 0. In such cases, all alphabets will have their preceding positions e.g. P will be on 15 and Z will be on 25.

2. If the question is asked that what comes after Z or at number 27 or 28, the alphabets will start repeating itself in that order. Like, A will come after Z at number 27 and B will come at 28]

Some more examples.

e.g. 1. In a certain code language, “MOTHER” is written as “OQVJGT”. How is “RELIEF” written in that code?

Ans- Here, we can see that each letter of “MOTHER” is moved two steps forward to obtain “OQVJGT”. So “RELIEF” should be written as “TGNKGH”. (Please look at the table above if you have any doubt.)

Isn’t it simple? Now, let’s look at a difficult one.

e.g. 2. In a certain code language, “CRASH” is coded as “XNXQG”. How is “TRAIN” written in that code?

Ans- For words “CRASH” and “XNXQG”, C is 5 steps ahead of X, R is 4 steps ahead of N, A is 4 steps ahead of X, S is 2 steps ahead of Q and H is 1 step ahead of G. So, in this pattern, “TRAIN” should be written as “ONXGM”.

Questions of backtracking can also come. Like, 

e.g. 3. In a certain code language, “CORNER” can be written as “EMTLGP”. In that language, what is the meaning of “UFCBQU”?

Ans- Here, the first, third and fifth letter of “CORNER” (from left) is moved two steps forward and second, the fourth and sixth letter is moved two steps backward. Or we can say, there is an alternating sequence of two steps forward and two steps backward. So, to decode “UFCBQU” we have to move first, third and fifth letter 2 steps back and second, fourth and sixth letter 2 steps forward. So, it will become “SHADOW”.

e.g. 4. In a certain code language, “BAT” can be written as 23. How is “RABBIT” written in that code?

Ans- Here, it we calculate the number corresponding to the letters of “BAT”, we got B + A + T = 1 + 2 + 20 = 23. So, “RABBIT” can be written as, R + A + B + B + I + T = 18 + 1 + 2 + 2 + 9 + 20 = 52. So, the answer is 52. 

e.g. 5. In a certain code language, “RAT” can be written as 18120. How is “MOUSE” written in that language?

Ans- This example is different from the previous one. In the previous example, we did the sum of the numbers corresponding to given letters. In this example, we write the corresponding numbers as digits of the answer, like, R comes at 18, A comes at 1 and T comes at 20. So, “RAT” becomes 18120. So, “MOUSE” becomes 131521195. (We have to decode the code by seeing the pattern in the code and the main word) 

e.g. 6. In a certain code language, “BRAIN” is written as “%$×+÷” and “TIER” is written as “#+*$”. How is “TRAIN” written in that code?

Ans- We can make a table of the signs for the corresponding words.

So, from this, it is clear that “TRAIN” can be written as “#$×+÷”.

e.g. 7. If ‘cat’ is called ‘blue’, ‘dog’ is called ‘pink’, ‘rat’ is called ‘black’ and ‘lion’ is called ‘orange’, who would bark?

Ans- We know that in these four animals, only dog barks. But the dog is called ‘pink’. So, ‘pink’ is the correct answer. 

e.g. 8. If ‘car’ is called ‘airplane’, ‘bike’ is called ‘cycle’, ‘aeroplane’ is called ‘bike’ and ‘cycle’ is called ‘car’, what would fly in sky?

Ans- We know that, aeroplane fly in the sky. But here aeroplane is bike. So, ‘bike’ is the correct answer. (Don’t get confused by the statement. We just have to focus on the exact answer and the changed name of answer and nothing else.) 

e.g. 9. If ‘ugh pri qus’ stands for ‘nice healthy breakfast’, ‘teh pri rps’ stands for ‘very good breakfast’ and ‘kim ugh ptr’ stands for ‘nice dinner together’, which word stands for ‘healthy’?

Ans- Here, ‘ugh pri qus’ → ‘nice healthy breakfast’. ‘teh pri rps’ → ‘very good breakfast’. Here, only one word is common in both the coded and decoded sentences. i.e. ‘breakfast’ and ‘pri’. So, ‘pri’ stands for ‘breakfast’. Also, ‘kim ugh ptr’ → ‘nice dinner together’. In first and third sentence, the common words are ‘nice’ and ‘ugh’. So ‘ugh’ stands for ‘nice’. So, in first sentence, ‘qus’ and ‘healthy’ are remaining. So, ‘qus’ stands for ‘healthy’. 

e.g. 10. In a certain code, ‘245’ stands for ‘study very hard’, ‘794’ stands for ‘hard work pays’ and ‘519’ stands for ‘study and work’, which word stands for ‘healthy’? Ans- Here, ‘245’ → ‘study very hard’, ‘794’ → ‘hard work pays’. Here, only one word and one number are common in both the coded and decoded sentences. i.e. ‘hard’ and ‘4’. So, ‘4’ stands for ‘hard’. Also, ‘519’ → ‘study and work’. In the first and third sentence, the common word and number is ‘study’ and ‘5’. So ‘5’ stands for ‘study’. So, in first sentence, ‘2’ and ‘very’ are remaining. So, ‘2’ stands for ‘very’.