Notes - Coding-Decoding
Category : 11th Class
Coding ? Decoding
Coding - Decoding
Learning Objectives
Coding-Decoding
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 student's ability to decipher the law that codes a particular message and to break the code to reveal the message.
Letter Coding
A particular letter stands for another letter in letter coding.
(a) UDHF
(b) UDFH
(c) HFDU
(d) UDFG
(e) None of these
Ans. (b)
Explanation:
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.
\[R\,\,\,\,\,\,\Leftrightarrow \,\,\,\,\,\,\,\,U\]
\[A\,\,\,\,\,\,\Leftrightarrow \,\,\,\,\,\,\,\,D\]
\[C\,\,\,\,\,\,\Leftrightarrow \,\,\,\,\,\,\,\,F\]
\[E\,\,\,\,\,\,\Leftrightarrow \,\,\,\,\,\,\,\,H\]
If 'REQUIRED' is coded as 'QERIUDER’, how SINGULAR would be coded?
(a) NISGURAL (b) SINU6RAL
(c) NISRALGU (d) NISUGRAL
(e) None of these
Ans. (d)
Explanation: In the given code/ option (d) is correct.
Here we have made three groups in coded letters & changed a series.
Similarly,
3. In certain code BROUGHT is written as PSCTUIH. How NIGHTED would be coded?
(a) FHMGCDS (b) FHMGEFU
(c) HJOGEFU (d) HJOIEFU
(e) None of these
Ans. (d)
Explanation:
4. In a certain coded BRIGHT is written as JSCSGF. How JOINED would be written in that code?
(a) JPKEFO
(b) JPKCDM
(c) HNIEFO
(d) JPKMDC
(e) None of these
Ans. (b)
In the given code 1st three letters are moved one step forward and last three letters are moved one step backward than the corresponding letter in the word.
5. In certain code JAYANTI is written as KCZCOVJ. How KANCHAN would be written in that code?
(a) LCOJECO
(b) LCOEIOC
(c) LCOEICO
(d) LCEICOO
(e) None of these
Ans. (c)
Explanation:
In the given code, continuous letters are added are step and two steps alternatively in forward order.
Similarly,
Decreasing order
1. In certain code ONIDA is written as USMGC. How would FRAUD be written in that code?
(a) LWEFX
(b) LWEXF
(c) LWEXE
(d) LEWXF
(e) None of these
Ans. (b)
Explanation:
2. In certain code JUICE is written as LYOKO. How would SONIA be written in that code?
(a) USTKQ (b) UTSKQ
(c) USTQK (d) SUKQT
(e) None of these
Ans. (c)
Explanation:
Similiarly,
Increasing to multiplication order
1. In certain code DEEF is written as DJOX. How would FEED be written in that code?
(a) FJPO (b) FRJO
(c) FPOJ (d) FJOP
(e) None of these
Ans. (d)
Explanation:
Similarly,
Adding of letters
1. If MAHESH is coded an DAHEJH, how HYDRATE would be coded?
(a) HGDIAGE
(b) HGJDABE
(c) HGDIABE
(d) HGDIAEB
(e) None of these
Ans. (d)
Explanation;
Therefore, HYDRATE will be coded as HGDIABE.
Number Coding
(a) 8312346
(b) 8321436
(c) 8312436
(d) 8313426
(e) None of these
Ans. (c)
Explanation:
Letter |
E |
A |
T |
C |
H |
I |
R |
Code |
3 |
1 |
8 |
2 |
4 |
5 |
6 |
The code for TEACHER is 8312436.
(a) 455978 (b) 544978
(c) 554978 (d) 733961
(e) None of these
Ans. (a)
Explanation:
Letter |
P |
A |
I |
N |
T |
E |
X |
C |
L |
Code |
7 |
4 |
1 |
2 |
8 |
9 |
3 |
5 |
6 |
The code for ACCEPT is 455978.
(a) 8312346 (b) 8321436
(c) 8312436 (d) 8313426
(e) None of these
Ans. (c)
Explanation:
Letter |
G |
L |
A |
R |
E |
M |
O |
N |
S |
Code |
6 |
7 |
8 |
1 |
0 |
2 |
3 |
9 |
5 |
The code for RANSOM is 189532.
(a) 8312346 (b) 8321436
(c) 8312436 (d) 8313426
(e) None of these
Ans. (c)
Explanation:
Letter |
D |
E |
L |
H |
I |
C |
A |
U |
T |
Code |
7 |
3 |
5 |
4 |
1 |
8 |
2 |
9 |
6 |
The code for CALICUT is 8251896.
(a) 381171
(b) 381191
(c) 832252
(d) 835545
(e) None of these
Ans. (b)
Explanation:
Letter |
E |
N |
G |
L |
A |
D |
F |
R |
C |
Code |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
The code for GREECE is 381191.
(a) 3
(b) 6
(c) 8
(d) 10
(e) None of these
Ans. (b)
Explanation: Clearly, each word is coded by the numeral which is twice the number of letters in the word.
So, CAR =
\[\left( Number\text{ }of\text{ }letters\text{ }m\text{ }CAR \right)\times 2=3\times 2=6.\]
(a) 768
(b) 875
(c) 876
(d) 886
(e) None of these
Ans. (c)
Explanation: In the given system of coding, a number x is coded as
\[(10-x).\]
Thus, 2 is coded as
\[\left( 10-2 \right)\]
i.e. 8, 3 as
\[\left( 10-3 \right)\]
i.e. 7 and 4 as
\[\left( 10-4 \right)\]
i.e. 6
So, 234 stands for 876
(a) 45 (b) 81
(c) 100 (d) 105
(e) None of these
Ans. (d)
Explanation: Clearly, in the given coding system, we have:
\[2={{2}^{2}}+1=5\,;\,4={{4}^{2}}+2=18\,;\,6={{6}^{2}}+3=39.\]
So,
\[10={{\left( 10 \right)}^{2}}+5=100+5=105.\]
Matrix Coding
Direction: In each of the following questions (A, B, C), a word is represented by only one set of numbers as given in any one of the alternatives. The sets of numbers given in the alternatives are represented by two classes of alphabets as in the two given matrices. The columns and rows of Matrix
\[{{I}^{st}}\]
are numbered from 0 to 4 and those of Matrix
\[I{{I}^{nd}}\]
from 5 to 9. A letter from these matrices can be represented first by its row and then the column number e.g., in the matrices for questions 1 to 4, M can be represented by 14, 21, etc; O can be represented by 20, 32, etc. Similarly you have to identify the correct set for the word given in each question.
Question-A
Most
(a) 40, 44, 22, 89 (b) 33, 20, 11, 79
(c) 21, 04, 03, 88 (d) 02, 13, 34, 56
(e) None of these
Ans. (d)
Explanation: From matrix I, M can be coded as 02, 14, 21, 33 or 40.
From matrix I, O can be coded as 01, 13, 20, 32, or 44.
From matrix I, S can be coded as 03, 10, 22, 34, or 41.
From matrix II, T can be coded as 56, 68, 75, 87, or 99.
Clearly (d) is the only set of correct codes.
ROAD
(a) 42, 32, 79, 58 (b) 23, 32, 98, 99
(c) 11, 13, 67, 69 (d) 04, 20, 55, 78
(e) None of these
Ans. (c)
Explanation: From matrix I, R can be coded as 04, 11, 23, 30, or 42.
From matrix I, O can be coded as 01, 13, 20, 32, or 44.
From matrix II, A can be coded as 55, 67, 79, 86, or 98.
From matrix II, D can be coded as 57, 69, 76, 88, or 95.
Clearly, only (c) contains the correct codes.
STOP
(a) 10,56,44,97
(b) 41,68,02,77
(c) 22,75,32,86
(d) 33,99,42,59
(e) None of these
Ans. (a)
Explanation: From matrix I, S can be coded as 03, 10, 22, 34 or 41.
From matrix II, T can be coded as 56, 68, 75, 87 or 99.
From matrix I, O can be coded as 01, 13, 20, 32 or 44.
For matrix II, P can be coded as 59, 66, 78, 85 or 97.
FOAM
(a) 24, 01, 55, 22
(b) 00, 01, 67, 33
(c) 12, 13, 67, 23
(d) 43, 52, 56, 33
(e) None of these
Ans. (b)
Explanation: From matrix I, F can be coded as 00, 12, 24, 31 or 43.
From matrix I, O can be coded as 01, 13, 20, 32 or 44,
From matrix II, A can be coded as 55, 67, 79, 86, or 98.
From matrix I, M can be coded as 02, 14, 21, 33 or 40.
Question-B
NEST
(a) 02, 56, 55, 59
(b) 14, 67, 66, 67
(c) 21, 76, 77, 76
(d) 33, 85, 88, 86
(e) None of these
Ans. (a)
Explanation: From matrix I, N can be coded as 02, 14, 21, 33 or 40.
From matrix II, E can be coded as 56, 67, 78, 85 or 97.
From matrix II, S can be coded as 55, 66, 77, 89 or 96.
From matrix II, T can be coded as 59, 68, 76, 87, or 95.
FAITH
(a) 43, 42, 41, 78, 89
(b) 31, 34, 23, 76, 79
(c) 24, 31, 10, 59, 57
(d) 12, 20, 40, 68, 65
(e) None of these
Ans. (b)
Explanation: From matrix J, F can be coded as 00, 12, 24, 31 or 43.
From matrix I, A can be coded as 01, 13, 20, 34 or 42.
From matrix S, I can be coded as 04, 10, 23, 32 or 41.
From matrix II, T can be coded as 59, 68, 76, 87 or 95.
From matrix II, H can be coded as 57, 65, 79, 86 or 98.
FINE
(a) 31, 32, 33, 82
(b) 24, 19, 21, 78
(c) 12, 10, 13, 67
(d) 00, 04, 02, 56
(e) None of these
Ans. (d)
Explanation: From matrix I, F can be coded as, 00, 12, 24, 31 or 43.
From matrix I, I can be coded as 04, 10, 23, 32 or 41.
From matrix I, N can be coded as 02, 14, 21, 33 or 40.
From matrix II, E can be coded as 56, 67, 78, 85, or 97.
HEAT
(a) 79, 53, 20, 87 (b) 65, 56, 13, 57
(c) 57, 56, 01, 59 (d) 29, 85, 34, 93
(e) None of these
Ans. (c)
Explanation: From matrix II, H can be coded as 57, 65, 79, 86 or 98.
From matrix II, E can be coded as 55, 67, 78, 85, or 97.
From matrix I, A can be coded as 01, 13, 20, 34 or 42.
From matrix I, T can be coded as 59, 68, 76, 87 or 95.
BOTH
(a) 88, 30, 85, 86 (b) 75, 22, 76, 79
(c) 69, 67, 68, 59 (d) 58, 02, 68, 65
(e) None of these
Ans. (b)
Explanation: From matrix II, B can be coded as 58, 69, 75, 88 or 99.
From matrix I, 0 can be coded as 03, 11, 22, 30 or 44.
From matrix II, T can be coded as 59, 68, 76, 87 or 95.
From matrix II, H can be coded as 57, 65, 79, 86 or 98.
Question-C
DRAW
(a) 41, 66, 23, 55 (b) 32, 75, 44, 76
(c) 23, 57, 30, 68 (d) 14, 89, 12, 78
(e) None of these
Ans. (d)
Explanation: From matrix I, D can be coded as 00, 14, 23, 32 or 41.
From matrix II, R can be coded as 57, 66, 75, 89 or 98.
From matrix I, A can be coded as 03, 12, 21, 30 or 44.
From matrix II, W can be coded as 55, 69, 78, 87 or 96.
BAND
(a) 43, 21, 97, 33 (b) 11, 21, 79, 41
(c) 34, 44, 66, 14 (d) 20, 30, 89, 23
(e) None of these
Ans. (b)
Explanation: From matrix I, B can be coded as 02, 11, 20, 34 or 41.
From matrix I, A can be coded as 03, 12, 21, 30 or 44.
From matrix II, N can be coded as 56, 65, 79, 88 or 97.
From matrix I, D can be coded as 00, 14, 23, 32 or 43.
BLOW
(a) 11, 68, 42, 69 (b) 21, 95, 33, 97
(c) 34, 68, 10, 88 (d) 34, 86, 44, 78
(e) None of these
Ans. (a)
Explanation: From matrix I, B can be coded as 02, 11, 20, 34 or 43.
From matrix II, L can be coded as 59, 68, 77, 86 or 95.
From matrix I, O can be coded as 01, 10, 24, 33 or 42.
From matrix II, W can be coded as 55, 69, 78, 87 or 96.
RAIN
(a) 57, 12, 31, 56 (b) 57, 21, 23, 79
(c) 66, 44, 42, 96 (d) 75, 30, 31, 87
(e) None of these
Ans. (a)
Explanation: From matrix II, R can be coded as 57, 66, 75, 89 or 98.
From matrix I, A can be coded as 03, 12, 21, 30 or 44.
From matrix I, I can be coded as 04, 13, 22, 31 or 40.
From matrix II, N can be coded as 56, 65, 79, 88 or 97.
LAMB
(a) 68,21,58,34 (b) 77,44,76,33
(c) 86,21,67,12 (d) 95,30,80,20
(e) None of these
Ans. (a)
Explanation: From matrix II, L can be coded as 59, 68, 77, 86 or 95.
From matrix I, A can be coded as 03, 12, 21, 30 or 44.
From matrix II, M can be coded as 58, 67, 76, 85 or 99.
From matrix I, B can be coded as 02, 11, 20, 34 or 43.
Substitution
In this type of questions, some particular words are assigned certain substituted names. The question asked is to be answered in the substituted code language only.
(a) Red (b) Green
(c) Yellow (d) Violet
(e) None of these
Ans. (c)
Explanation: The colour of the human blood is 'red' and as given, 'red' is called 'yellow'. So the colour of human blood is 'yellow'.
(a) Apricots (b) Apples
(c) Chilies (d) Bananas
(e) None of these
Ans. (d)
Explanation: "Chilies’ are green in colour and as given, 'chilies' are 'bananas'. So, 'bananas' are green in colour.
(a) Cloud (b) Sky
(c) Star (d) Earth
(e) None of these
Ans. (c)
Explanation: Birds fly in the 'sky' and as given, 'sky' is 'star'. So birds fly in the 'star'. HI If 'black' means 'pink', 'pink' means 'blue', 'blue' means 'whiter 'white' means 'yellow', 'yellow' means 'red' and 'red' means 'brown', then what is the color of clear sky?
(a) Brown
(b) Red
(c) Blue
(d) Pink
(e) None of these
Ans. (d)
Explanation: The color of clear sky is 'blue'. But, as given, 'pink' means 'blue'. So, the colour of clear sky is 'pink'.
Commonly Asked Questions
4. If 'dust' is called 'air", 'air' is called 'fire', 'fire' is called 'watery 'water' is called 'colour', 'colour' is called 'rain' and 'rain' is called 'dust', then where do fish live?
(a) Fire (b) Water
(c) Colour (d) Dust
(e) None of these
Ans. (c)
Explanation: Fishes live in 'water' and as given, 'water' is called 'colour'. So, fishes live in 'colour'.
5. If 'blue' means 'green’, 'green' means 'whiter 'white' means 'yellow', 'yellow' means 'black’, 'black' means 'red' and 'red' means 'brown', then what is the colour of milk?
(a) Black (b) Green
(c) Blue (d) Yellow
(e) None of these
Ans. (b)
Explanation: The colour of milk is 'white'. But, as given, 'green' means 'white'. So, the colour of milk is 'green'.
6. If, in a language, 'finger' is called 'toe', 'toe' is called 'foot', 'foot' is called 'thumb', 'thumb' is called 'anklet 'ankle' is called 'plam' and 'plam' is called 'knee', then in that language, what will an illiterate man put to mark his signature?
(a) Toe (b) Knee
(c) Thumb (d) Ankle
(e) None of these
Ans. (d)
Explanation: Clearly, an illiterate man puts his 'thumb' to mark his signature. But, as given, 'thumb' is called 'ankle'. So, an illiterate man will put his 'ankle' to mark his signature.
7. On another planet, the local terminology for 'earthy 'watery 'light', 'air' and 'sky' are 'sky', 'light' 'air', 'water' and 'earth' respectively. If someone is thirsty there, what would he drink?
(a) Light (b) Air
(c) Sky (d) Water
(e) None of these
Ans. (a)
Explanation: One drinks 'water' when one is thirsty. Since 'water' is called 'light' on the other planet, so one would drink 'light' when thirsty.
8. If the animals those can walk are called 'swimmers', crawling animals are called 'flyers', those living in water are called 'snakes' and those fly in the sky are called 'hunters', then what will a lizard be called?
(a) Swimmers (b) Snakes
(c) Flyer (d) Hunters
(e) None of these
Ans. (c)
Explanation: Clearly, a lizard crawls and the animals that crawl are called ‘flyer’.
So, a lizard is called 'flyer'.
Deciphering Message word Codes
In this type of questions, some messages are given in the coded language and the code for a particular word or message is asked. To analyse such codes, any two messages bearing a common word are picked up. The common code-word will thus represent that word. Proceeding similarly by picking up all possible combinations of two, the entire message can be decoded and the code for individual word is found.
Example:
(a) std (b) dim
(c) bro (d) cus
(e) None of these
Ans. (d)
Explanation: In the third statement, the code-word 'pus' occurs twice and the word 'the' also occurs twice. So, the code - word for 'the' is 'pus'.
Now in the first and third statements, the common code-word 'pus' stands for 'the'.
So, the other common code-word 'bro' stands for the other common word i.e. 'cat'.
Similarly, in the second and third statements, the common code-word 'dim' stands for the common word 'dog'. Thus, in the third statements, the remaining code-word i.e; 'cus' stands for 'has'.
Direction: According to a certain code,
(a) 'min fin bin gin' means 'trains are always late';
(b) 'gin din cin hin' means 'drivers were always punished';
(c) 'bin cin uin rin' means 'drivers stopped all trains'; and
(d) 'din kin fin vin' means 'all passengers were late'.
(a) min cin din (b) fin cin din
(c) fin din gin (d) gin hin min
(e) None of these
Ans. (b)
Explanation: In the second and third statements, the common code - word is 'cin' and the common word is "drivers'. So 'cin' means 'drivers'.
In the second and fourth statements, the common code - word is 'din' and the common word is 'were'. So 'din' means 'were'.
In the first and fourth statements, the common code-word is 'fin' and the common word is 'late'. So, 'fin' means 'late'.
Thus, the required code will be a combination of 'cin', 'din' and 'fin'.
(a) all (b) late
(c) trains (d) drivers
(e) None of these
Ans. (a)
Explanation: (a) In the third and fourth statements, the common code-word is 'vin' and common word is 'all'. So 'vin' represents 'all'.
(a) Always late trains (b) Passengers are punished
(c) All passenger trains (d) Passengers are late
(e) None of these
Ans. (b)
Explanation: We know that in the second statement, 'cin' means 'drivers' and 'din' means 'were'. In the first and second statements, the common code-word is 'gin' and the common word is 'always'. So 'gin' means 'always'. Thus, in the second statement, 'hin' means 'punished'.
Now, in the first statement, 'fin' means 'late' and 'gin' means 'always'.
In the first and third statements, the common code-word is 'bin' and the common word is 'trains'. So, 'bin' means 'trains'.
Thus, in the first statement, 'min' means 'are'.
In the fourth statement, 'din' means 'were', 'fin' means 'late' and 'vin' means 'all'.
So, 'kin' means 'passengers'. Hence, 'hin min kin' would mean 'passengers are punished'.
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