Coding-Decoding
In this segment of common sense reasoning, secret messages or words have to be decoded. They are coded as per a definite pattern/ rule which should be identified first. Then the same is applied to decode another coded word. This chapter makes you familiar with every type of problem based on coding-decoding.
Types of Coding-Decoding
Type 1: Letter Coding
In this type of question, the code of words is given in the form of letters of the alphabet.
- RSRFQSJ
- RSRDQSJ
- RRSFQSJ
- RSRFJSQ
Sol (1): As,
Similarly,
I. STRONG
- VBDERE
- VBDEER
- VBEDFR
- VBDEFR
II. ISLAND
- JVQUFZ
- ZFUQVJ
- QUFZJV
- FUZJVQ
Sol: Here each letter of the original sentence is represented by a different code as shown below:
Sentence | GANDHI | WAS | A | GREAT | LEADER | OF | INDIA |
Code | RUFZOJ | SUV | U | RDTUB | QTUZTD | EP | JFZJU |
Hence the code for STRONG is VBDEFR and the code for ISLAND is JVQUFZ.
- MBZ
- NBZ
- MCZ
- MBY
Solution (1): MBZ
As | Similarly |
R (+1) → S | L (+1) → M |
U (+1) → V | A (+1) → B |
N (+1) → O | Y (+1) → Z |
∴ LAY should be MBZ.
- UOJKLAN
- UOJRMAN
- UOJRLBN
- UOJRLAM
Solution (1): UOJRLAN
Clearly, when COURAGE is coded, some letters are interchanged with respect to their positions, i.e., odd position are interchanged.
Position of 1 changes to 3 and 3 to 1. Position of 5 changes to 7 and 7 to 5.
Hence, JOURNAL can be coded as UOJRLAN.
Type 2: Number Coding
In this type of coding, either alphabetical code values are assigned to the numbers or numerical code values are assigned to words.
- 50
- 19
- 37
- 55
Solution (1): 50
Clearly, in the given code, A = 1, B = 2, C = 3, ….. so that.
COVER = 3 + 15 + 22 + 5 + 18 = 63
∴ BASIS = 2 + 1 + 19 + 9 + 19 = 50.
- 633185
- 185336
- 363815
- 581363
Solution (2): 185336
In this code, the alphabets are coded as follows:
S I S T E R | U N C L E | B O Y |
5 3 5 3 0 1 | 8 4 6 7 0 | 1 2 9 |
If we apply this method, RUSTIC is coded as 185336.
Type 3: Substitution Coding
In substitution coding, some particular objects are assigned as code names and then a question is asked that is to be answered in the code language.
- Door
- Ventilator
- Roof
- Floor
Solution: Since a person stands on the floor and in the given code language floor is called roof. Hence, roof will be the correct answer.
Type 4: Mixed Letter Coding
In this type of question, three or more sentences are given in the coded language and the code for a particular word is asked. To find the code for the particular word, pickup two sentences bearing a common word and the common code word will mean that word. Proceeding in a similar manner, we can be determined a particular code word for each word of given sentences.
- ja
- ma
- kop
- top
Solution. (1): In that language ‘ja’ means ‘Asha’
po ki top ma | → | Usha is playing cards |
kop ja ki ma | → | Asha is playing tennis |
ki top sop ho | → | they are playing football |
po sur kop | → | cards and tennis |
Comparing relation in each of the statements, we get Asha is coded as ‘ja’.
Type 5: Condition-based coding
In this type of coding-based question, a set of letters and their codes are given. After that, some conditions are given based on the combination of numbers/symbols. You have to solve the questions using these conditions.
Directions: Select the code of the given letter group in each question based on the following coding system and conditions.
Conditions:
- (i) If the first letter is a consonant and the last letter is a vowel, the codes for the first and last letters are to be interchanged.
- (ii) If the first and the last letter are vowels, both are to be coded as the code of the first letter.
- (iii) If both the first and last letters are consonants, both are to be coded as ‘δ’.
- 6#25@7
- 7#25@6
- 62#5@7
- 6#25@6
Solution (1): 6#25@7
I | D | Z | Q | G | Y |
6 | # | 2 | 5 | @ | 7 |
- 32146$
- $21463
- δ2146δ
- 321463
Solution (3): δ2146δ
M | Z | A | E | I | K |
δ | 2 | 1 | 4 | 6 | δ |
Condition (iii) is applied.
- @5463*
- δ5463*
- 3546*@
- none of these
Solution (4): δ546*δ
I | D | Z | Q | G | Y |
δ | 5 | 4 | 6 | * | δ |
Condition (iii) is applied.
- ©*457%©
- ©*457©
- %*457%©
- %*457%
Solution (2): ©*457©
U | F | E | Q | Y | O |
© | * | 4 | 5 | 7 | © |
Condition (ii) is applied.
- 843#76
- 843#78
- δ43#7δ
- 643#78
Solution (4): 643#78
N | E | M | D | Y | I |
6 | 4 | 3 | # | 7 | 8 |
Condition (i) is applied.
Type 6: Coded Letter of Word
These types of questions are based on code language which utilizes letters in the English alphabet.
Directions: In each question, there is a word written in capital letter, with one letter underlined. For each letter in that word, there is a code written in small letters. That code is denoted by 1, 2, 3, 4, and 5, not in the same order. You have to find out the exact code for the underlined letter in the word.
- hj
- su
- tv
- pr
- df
Solution. (4): Correct code for letter ‘Q’ is ‘pr’
Each letter in word QUITE is expressed as two letters, one behind and the other ahead of the given letter. Therefore, ‘A’ becomes ‘zb’, ‘B’ comes ‘ac’, and so on.
- R
- O
- H
- Q
- I
Solution. (4): Correct code for letter ‘R’ is ‘Q’
Each letter in the word PRISM is coded as one letter behind. Therefore, ‘A’ becomes ‘z’, ‘B’ comes ‘a’, and so on.
- e
- w
- d
- h
- v
Solution. (2):
Each letter in the word BEAST is coded as three letters ahead. Therefore, ‘A’ becomes ‘d’, ‘B’ comes ‘e’, and so on.
Solved Examples
- FVLFNHW
- FULFNHW
- FUNFNHW
- FULFMHW
Solution (2): FULFNHW
As,
Similarly
- 23153
- 24154
- 24253
- 24153
Solution (4): 24153
codes for letters are: P=2, E=4, A=1, R=5 and L=3
- lon
- tir
- sig
- fin
Solution (1): ‘lon’
Common code from first and third statement for ‘fin’ is ‘fruit’. From second and third statement, ‘sig’ is ‘lily’. So ‘lon’ means ‘and’ in third statement.
- NPTQL
- NPTSL
- NQTSL
- NPTSM
Solution (2): NPTSL
and
So,
∴ 23549 can be written in code as NPTSL.
- RURODBS
- RTRODBS
- RTQODBS
- RTROEBS
Solution (2): RTRODBS
Clearly, we can see that each letter of the word DELHI is moved one step backward to obtain the code. Similarly, SUSPECT will be coded as RTRODBS.