CODING AND DECODING
Note: Question numbers are numbers from the actual exam in the respective years mentioned below
12. Consider the following matrix :(2015)
| 3 | 8 | 10 | 2 | ? | 1 |
| 6 | 56 | 90 | 2 | 20 | 0 |
What is the missing number at ? in the matrix?
(a) 5
(b) 0
(c) 7
(d) 3
Answer (a)
In each column, the number in the second row is the product of the number in the first row and its predecessor.
- 6 =3x2
- 56 = 8x7
- 90 = 10x9
- 2 =2x1
- 0 = 1x0
- 20 = 5x4
Therefore,5 comes in place of the question mark
13. What is the missing number X' of the series 7, X, 21, 31, 43?
(a) 11
(b) 12
(c) 13
(d) 14
Answer (c)
The number series is a simple addition series.
The difference between the two consecutive numbers are increasing by two.
Hence, 13 will replace 'X' in the series above.
61. A military code writes SYSTEM as SYSMET and NEARER as AENRER.
Using the same code, FRACTION can be written as :(2016)
(a) CARFTION
(b) FRACNOIT
(c) NOITCARF
(d) CARFNOIT
Answer (d)
The code reverses the first half of the word and the second half of the word separately.
4 2017
60. In a certain code, '256' means' red colour chalk', '589' means 'green colour flower' and' 254' means ‘white colour chalk'. The digit in the code that indicates ‘white' is
(a) 2
(b) 4
(c) 5
(d) 8
Answer (b)
In the code, 256 means red colour chalk, 589 means green colour flower and 254 means white colour chalk.
The digit 2 is common in both 256 and 254, and the word chalk is common in both 256 and 254. This means that 2 represents chalk.
The digit 5 is common in both 256 and 589, and the word colour is common in both 256 and 589. This means that 5 represents colour.
The digit 8 is only present in 589, and the word flower is only present in 589. This means that 8 represents flower.
The digit 4 is only present in 254, and the word white is only present in 254. This means that 4 represents white.
21. If LSJXVC is the code for MUMBAI, the code for DELHI is (2018)
(a) CCIDD
(b) CDKGH
(c) CCJFG
(d) CCIFE
Answer (a)
The code for DELHI is CCIDD.
The code for MUMBAI is LSJXVC.
The code is generated by shifting the letters of the word by 4 positions forward.
So, the code for DELHI is CCIDD.
(a) 92233
(b) 92323
(c) 93322
(d) 93232
Answer (b)
If RAMON is written as 12345 and DINESH as 675849, then HAMAM will be written as 92323.
The code is generated by assigning a unique number to each letter of the alphabet. The numbers are then arranged in the order of the letters in the word.
So, the code for RAMON is 12345 because R = 1, A = 2, M = 3, O = 4, and N = 5.
The code for DINESH is 675849 because D = 6, I = 7, N = 5, E = 8, S = 4, and H = 9.
The code for HAMAM is 92323 because H = 9, A = 2, M = 3, A = 2, and M = 3.
4/12/95, 1/1/96, 29/1/96, 26/2/96, ..
What is the next term of the series?(2018)
(a) 24/3/96
(b) 25/3/96
(c) 26/3/96
(d) 27/3/96
Answer (b)
The sequence is a series of dates, with each date being 28 days after the previous date.
The first date is 4/12/95. The next date is 1/1/96, which is 28 days after 4/12/95. The next date is 29/1/96, which is 28 days after 1/1/96. The next date is 26/2/96, which is 28 days after 29/1/96.
The next date in the sequence is 25/3/96, which is 28 days after 26/2/96.
- + 1• + 2• + •3+ •1=21•
In the above sum, • stands for
(a) 4
(b) 5
(c) 6
(d) 8
Answer (d)
Let's consider each option in turn.
(a) If • stands for 4, then the sum is 4 + 14 + 24 + 43 + 41 = 126. This is not equal to 21•, so this option is incorrect.
(b) If • stands for 5, then the sum is 5 + 15 + 25 + 53 + 51 = 154. This is not equal to 21•, so this option is incorrect.
(c) If • stands for 6, then the sum is 6 + 16 + 26 + 63 + 61 = 172. This is not equal to 21•, so this option is incorrect.
(d) If • stands for 8, then the sum is 8 + 18 + 28 + 83 + 81 = 218. This is equal to 21•, so this option is correct.
Therefore, the answer is (d), 8.
8 10 15 13
6 5 7 4
4 6 8 8
_ _ _ _
6 11 16 ?
What is the number at ? in the above pattern?(2018)
(a) 17
(b) 19
(c) 21
(d) 23
Answer (a)
In each column, the fourth element is equal to the sum of the first and third elements minus the second element.
The answer is 17.
The fourth element in the fourth column is equal to the sum of the first and third elements minus the second element. In this case, the first element is 6, the third element is 12, and the second element is 11. Therefore, the fourth element is equal to 6 + 12 - 11 = 17.
In the first column, the fourth element is 10, which is equal to the sum of the first element, 8, and the third element, 12, minus the second element, 10.
In the second column, the fourth element is 5, which is equal to the sum of the first element, 6, and the third element, 8, minus the second element, 7.
And in the third column, the fourth element is 13, which is equal to the sum of the first element, 4, and the third element, 8, minus the second element, 6.
(a) 74
(b) 75
(c) 76
(d) 77
Answer (c)
The sequence is decreasing by 3, 5, 7, 11, 13, 17, etc. These are the first few prime numbers. So, the next prime will be 17. The value of X will be 93 - 17 = 76.
51. What is X in the sequence 4, 196, 16, 144, 36, 100, 64, X?(2019)
(a) 48
(b) 64
(c) 125
(d) 256
Answer (b)
The sequence is a series of squares, with each square being the square of the number before it.
The first number in the series is 4. The next number is 16, which is the square of 4. The next number is 36, which is the square of 6. The next number is 100, which is the square of 10.
The next number in the series is 64, which is the square of 8.
Therefore, the answer is (b), 64.
68. If every alternative letter of the English alphabet from B onwards (including B) is written in lowercase (small letters) and the remaining letters are capitalized, then how is the first month of the second half of the year written ?(2019)
(a) JuLY
(b) jULy
(c) jUly
(d) jUIY
Answer (d)
If we start with the letter 'B' and alternate between lowercase and uppercase, we have the following pattern:
- B -> b
- C -> C
- D -> d
- E -> E
- F -> f
- G -> G
- H -> h
- I -> I
- J -> j
- K -> K
- L -> l
- M -> M
- N -> n
- O -> O
- P -> p
- Q -> Q
- R -> r
- S -> S
- T -> t
- U -> U
- V -> v
- W -> W
- X -> x
- Y -> Y
- Z -> z
Therefore, applying this pattern to the first month of the second half of the year, which is "July," we get "jUIY" as the correct answer.
So, the correct option is (d) jUIY.
70. In the sequence 1, 5, 7, 3, 5, 7, 4, 3, 5, 7, how many such 5s are there which are not immediately preceded by 3 but are immediately followed by 7?(2019)
(a) 1
(b) 2
(c) 3
(d) None
The answer is (a), 1.
There are three 5s in the sequence: 1, 5, 7, 3, 5, 7, 4, 3, 5, 7. Of these, two are preceded by 3 and followed by 7: 3, 5, 7 and 3, 5, 7. Only one 5 is not preceded by 3 but is followed by 7: 1, 5, 7.
(a) 0
(b) 1
(c) 2
(d)9
Answer (d)
Given that $ means 'divided by' ; @ means 'multiplied by'; # means 'minus'.
Then, 10#5@1$5 can be written as 10 - 5 * 1 / 5.
Following BODMAS, we first do the division, then the multiplication, and then the subtraction.
10 - 5 * 1 / 5 = 10 - 5 * 0.2 = 10 - 1 = 9.
Therefore, the value of 10#5@1$5 is 9.
(a) 2
(b) 3
(c) 4
(d) 5
Answer (b)
Given that X+1x+5x +xx+x1 =1xx.
If x=3, then 3+13+53 +33+31 = 133.
Therefore, the symbol x stands for 3.
abab_b_bcb_dcdcded_d
The missing letters which complete the arrangement are
(a) a, b, c, d
(b) a, b, d, e
(c) a, c, c, e
(d) b, c, d, e
Answer (c)
The arrangement is a series of repeating patterns, with each pattern being two letters long. The first pattern is "ab", the second pattern is "bc", the third pattern is "cd", and the fourth pattern is "de". The missing letters are the second letters of the third and fourth patterns, which are "c" and "e".
Therefore, the missing letters which complete the arrangement are a, c, c, e.
48. The letters from A to Z are numbered from 1 to 26 respectively.
If GHI=1578 and DEF = 912, then what is ABC equal to?(2020)
(a) 492
(b) 468
(c) 262
(d) 246
Answer (d)
The letters from A to Z are numbered from 1 to 26 respectively. Therefore, A = 1, B = 2, C = 3, D = 4, E = 5, F = 6, G = 7, H = 8, I = 9, and so on.
Given that GHI = 1578 and DEF = 912.
GHI = 1578 = 789 * 2.
DEF = 912 = 456 * 2.
Therefore, ABC = 123 = 246.
Therefore, the answer is (d), 246.
ACPO: BESU:: MNGI: @ (2020)
(a) NPJL
(b) NOJM
(c) NPIL
(d) NPJM
Answer (d)
The pattern is +1, +2, +3, +4.
A + 1 = B; C + 2 = E; P + 3 = S; O + 4 = U.
Similarly, M + 1 = N; N + 2 = P; G + 3 = J; I + 4 = M.
So the correct option is (d) as MNGI will become NPJM.
26. Replace the incorrect term by the correct term in the given sequence
3, 2, 7, 4, 13, 10, 21, 18, 31, 28, 43, 40 where odd terms and even terms follow the same pattern.(2021)
(a) 0
(b) 1
(c) 3
(d) 6
Answer (a)
The odd terms in the sequence follow the pattern +4, +6, +8, +10, +12. The even terms in the sequence follow the pattern +2, +4, +6, +8, +10. The first term in the even sequence should be 0, so that the pattern is consistent.
Therefore, the correct term to replace 2 is 0.
27. Following is a matrix of certain entries. The entries follow a certain trend row-wise. Choose the missing entry (?) accordingly.
| 7B | 10A | 3C |
| 3C | 9B | 6A |
| 10A | 13C | ? |
(a) 9B
(b) ЗА
(c) 3B
(d) 3С
Answer (c)
- 10 - 7 = 3 ,so 3C in the first row
- 9 - 3 = 6 , so 6A in second row
- 13 - 10 = 3
So answer is 3B
Sequence-I: 8 4 6 15 52.5 236.25
Sequence-II : 5 A B C D E
What is the entry in the place of C for the Sequence-II?(2021)
(a) 2.5
(6) 5
(c) 9.375
(d) 32.8125
Answer (c)
The pattern in the first sequence is:
- 8
- 8/2 = 4
- 4 * 3/2 = 6
- 6 * 5/2 = 15
- 15 * 7/2 = 52.5
- 5 * 9/2 = 236.25
The pattern in the second sequence is the same, but starting with 5.
- 5
- 5/2 = 2.5
- 5 * 3/2 = 3.75
- 75 * 5/2 = 9.375
- 375 * 7/2 = 32.8125
- 8125 * 9/2 = 148.4375
Therefore, the entry in the place of C is 9.375.
(a) N
(b) T
(c) H
(d) I
Answer (b).
The English alphabet is written in the following order:
- A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
The first 4 letters are written in opposite order, and the next 4 letters are written in opposite order and so on; and at the end Y and Z are interchanged.
- Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
The 13th letter is P. The fourth letter to the right of P is T.
Therefore, the fourth letter to the right of the 13th letter is T.
(a) 603
(b) 605
(c) 607
(d) 608
Answer (c)
The pattern in the sequence is:
- 2
- 2 + 5 = 7
- 7 + 3 * 5 = 7 + 15 = 22
- 22 + 3 * 15 = 22 + 45 = 67
- 67 + 3 * 45 = 67 + 135 = 202
- 202 + 3 * 135 = 202 + 405 = 607
- 607 + 3 * 405 = 607 + 1215 = 1822
Therefore, the value of X is 607.
How is 'CHEMISTRY written in that code language?(2021)
(a) DIDLHRSSX
(b) BIDNHTSSX
(c) BIDLHTSSX
(d) DGFLIRUQZ
Answer (b)
In the code language, each letter is represented by the letter that is two places to its right in the alphabet. For example, M is represented by L, A is represented by B, and so on.
Therefore, CHEMISTRY is written as BIDNHTSSX.
65. In the series _b_a_ba_b_abab_aab; fill in the six blanks ( _ ) using one of the following given four choices such that the series follows a specific order.
(a) bababa
(b) baabba
(c) bbaabb
(d) ababab
Answer (d)
The series is a repetition of the pattern "abb, aab". The first three letters are "abb", followed by "aab". The next three letters are "abb" again, followed by "aab" again, and so on.
(a) 13
(b) 14
(c) 15
(d) 16
Answer (b)
There are 21 consonants in the English alphabet.
Of these, 7 are symmetrical (B, C, D, H, I, O, X). This means that their mirror images look the same as their original shapes.
The remaining 14 consonants are asymmetrical (A, F, G, J, K, L, M, N, P, Q, R, S, T, V, W, Y, Z). This means that their mirror images do not look the same as their original shapes.
29. In the series AABABCABCDABCDE.., which letter appears at the 100th place?(2022)
(a) G
(b) H
(c) I
(d) J
Answer (c)
The series is a repetition of the pattern "A, AB, ABC, ABCD, ABCDE". The first five letters are "A, AB, ABC, ABCD, ABCDE". The next five letters are "A, AB, ABC, ABCD, ABCDE" again, and so on.
The 100th letter is the 9th letter in the pattern, which is "I".
(a) 248
(b) 252
(c) 258
(d) 262
Answer (c)
The sequence is a series of squares and cubes.
- The first term is 2, which is the square of 1.
- The second term is 12, which is the cube of 2.
- The third term is 36, which is the square of 6.
- The fourth term is 80, which is the cube of 4.
- The fifth term is 150, which is the square of 12.
- The sixth term is 252, which is the cube of 6.
Therefore, the value of X in the sequence is 252.
(a) OGXPMLD
(b) OGXQMLE
(c) OFXPMLE
(d) OFXPMLD
Answer (d)
If we reverse the order of the English alphabet, then 'A' becomes 'Z', 'B' becomes 'Y', 'C' becomes 'X', and so on. So, 'L' which is the 12th letter from the beginning of the alphabet becomes the 12th letter from the end, which is 'O'. Similarly, 'U' becomes 'F', 'C' becomes 'X', 'K' becomes 'H', 'N' becomes 'M', and 'O' becomes 'L'.
Therefore, the given word "LUCKNOW" becomes "OFXPMLD" when we reverse the order of the English alphabet and replace each letter with the letter whose position it occupies. Hence, the answer is option (d) OFXPMLD.
(a) 105
(b) 120
(c) 150
(d) 225
Answer (d)
The sequence is a series of numbers that are multiplied by 1/2, 3/2, 5/2, 7/2, and so on. The first term is 20, which is multiplied by 1/2 to get 10. The second term is 10, which is multiplied by 3/2 to get 15. The third term is 15, which is multiplied by 5/2 to get 30. The fourth term is 30, which is multiplied by 7/2 to get 75. The fifth term is 75, which is multiplied by 9/2 to get 225.
Therefore, the value of X in the sequence is 225.
