Series Completion
This section deals with questions in which series of numbers or letters are given. The term follows a certain pattern throughout.
The candidate is required to recognise this pattern either to complete the given series with the most suitable alternative or
to find the wrong term in the series.
NUMBER SERIES
Eg. 1 Which number would replace the question mark (?) in the series 2, 7, 14, 23, ?, 47
(1) 28 (2) 34 (3) 31 (4) 38 (5) None
Ans: The given sequence is +5, +7, +9, ——
ie. 2+ 5 = 7, 7 + 7 = 14, 14 + 9 = 23
Missing Number = 23 + 11 = 34.
2. Which is the number that should come next in the following series?
4, 6, 12, 14, 28, 30, ——
(1) 32 (2) 64 (3) 62 (4) 60 (5) None
Ans: The given sequence is a combination of two series 4, 12, 28, .... and 6, 14, 30, .... Clearly the number to be
found belongs to the first series. Now the pattern followed is +8, +16, +32.
So, missing number = (28 + 32) = 60
Hence the answer is (4)
3. Find the wrong number in the series.
7, 28, 63, 124, 215, 342
(1) 7 (2) 28 (3) 124 (4) 215 (5) None
Ans: The correct sequence is 23 - 1, 33 - 1, 43 - 1, ...etc.
Here 28 is wrong; so the answer is (2)
ALPHABET SERIES
Alphabet series consists of letters of the alphabet placed in a specific pattern. If you keep in your mind the order of
the letters with their respective numbers it will help you answer the questions quickly.
1 2 3 4 5 6 7 8 9 10 11 12 13
A B C D E F G H I J K L M
26 25 24 23 22 21 20 19 18 17 16 15 14
14 15 16 17 18 19 20 21 22 23 24 25 26
N O P Q R S T U V W X Y Z
13 12 11 10 9 8 7 6 5 4 3 2 1
Eg: 4 What will be the next term in
BKS, DJT, FIU, HHV, ?
(1) IJX (2) IGX (3) JGW (4) IGU (5) JGU
Ans: (3). In each term, the first letter is moved two steps forward, the second letter one step backward and
the third letter one step forward to obtain the corresponding letter of the next term. So, the missing term is JGW.
LETTER SERIES
This type of question usually consists of a series of small letters which follow a certain pattern. However some
letters are missing from the series. These missing letters are then given in a proper sequence as one of the
alternatives. The candidate is required to choose this alternative as the answer.
Eg: 5. aab - aaa - bba -
(1) baa (2) abb (3) bab (4) aab (5) bbb
1. The first blank space should be filled in by ‘b’ so that we have two a’s followed by two bs.
2. The second blank space should be fiiled in either by ‘a’. So that we have four as followed by two bs or by ‘b’.
So that we have three as followed by three bs.
3. The last space must be filled in by ‘a’.
4. Thus we have two possible answers - ‘baa’ and ‘bba’. But only ‘baa’ appears in the alternatives. So the answer
is (1).
5. In case we had both the possible answers in the alternatives, we should choose the one that forms a more
prominent pattern, which is aabb/aaabbb/aa. and our answer would have been ‘bba’.
Speed Developing Practice Test No. 6
Directions: In each of the following questions a number series is given with one term missing. Choose the correct
alternative that will continue the same pattern and fill in the blank spaces.
1. 4, 9, 13, 22, 35, ——
(1) 57 (2) 70 (3) 63
(4) 75 (5) None of these
2. 11, 13, 17, 19, 23, 29, 31, 37, 41, ——
(1) 43 (2) 47 (3) 51
(4) 53 (5) None of these
3. 15, 31, 63, 127, 255, ——
(1) 513 (2) 511 (3) 517
(4) 523 (5) None of these
4. 5, 11, 17, 25, 33, 43, ——
(1) 49 (2) 51 (3) 52
(4) 53 (5) None of these
5. 9, 12, 11, 14, 13, ——, 15
(1) 12 (2) 16 (3) 10
(4) 17 (5) None of these
Directions: In each of the following questions, one term in the number series is wrong. Find the wrong term.
6. 125, 126, 124, 127, 123, 129
(1) 123 (2) 124 (3) 126
(4) 127 (5) 129
7. 10, 26, 74, 218, 654, 1946, 5834
(1) 26 (2) 74 (3) 218
(4) 654 (5) 1946
8. 1, 2, 6, 15, 31, 56, 91
(1) 31 (2) 15 (3) 56
(4) 91 (5) 2
9. 3, 7, 15, 39, 63, 127, 255, 511
(1) 39 (2) 15 (3) 7
(4) 63 (5) 127
10. 56, 72, 90, 110, 132, 150
(1) 72 (2) 90 (3) 110
(4) 132 (5) 150
Directions: In each of the following questions, various terms of a letter series are given with one term missing. Choose the missing term out of the given alternatives.
11. cmw, hrb, ——, rbl, wgq, blv
(1) mwg (2) lvf (3) lwg
(4) mxg (5) wmx
12. DKY FJW HIU JHS ——
(1) KGR (2) LFQ (3) KFR
(4) LGQ (5) None of these
13. —— siy oeu kaq gwm csi
(1) wne (2) wnb (3) vne
(4) vme (5) None of these
14. BXJ ETL HPN KLP ——
(1) NHR (2) MHQ (3) MIP
(4) NIR (5) None of these
15. QPO, SRQ, UTS, WVU, ——
(1) XVZ (2) ZYA (3) YXW
(4) VWX (5) AZY
16. P3C, R5F, T8I, V12L, ——
(1) Y17O (2) X17M (3) X17O
(4) X16O (5) None of these
17. D-4, F-6, H-8, J-10, ——, ——
(1) K-12, M-13 (2) L-12, M-14 (3) L-12, N-14
(4) K-12, M-14 (5) K-12, N-14
18. G, H, J, M, ——, V
(1) T (2) S (3) R
(4) U (5) Q
19. OTE PUF QVG RWH ——
(1) SYJ (2) TXI (3) SXJ
(4) SXI (5) QWD
20. BD GI LN QS ——
(1) TV (2) VW (3) WX
(4) WY (5) VX
Directions: In each of the following letter series, some of the letters are missing which are given in that order as one of
the alternatives below it. Choose the correct alternative.
21. ba-ba - bac - acb - cbac
(1) aacb (2) bbca (3) ccba
(4) cbac (5) None of these
22. adb - ac - da - cddcb - dbc - cbda
(1) bccba (2) cbbaa (3) ccbba
(4) bbcad (5) None of these
23. a - ba - cbaac - aa - ba
(1) ccbb (2) cabc (3) cbcb
(4) bbcc (5) None of these
24. - bc - - b - aabc
(1) acac (2) babc (3) abab
(4) aacc (5) None of these
25. b - b - bb - - bbb - bb - b
(1) bbbbba (2) bbaaab (3) ababab
(4) aabaab
Answers:
1. (1) 2. (1) 3. (2) 4. (4) 5. (2) 6. (5) 7. (4) 8. (4) 9. (1) 10. (5) 11.
(1) 12. (4) 13. (5) 14. (1) 15. (3) 16. (3) 17. (3) 18. (5) 19. (4) 20. (5) 21. (3)
22. (2) 23. (2) 24. (1) 25. (3)
Explanatory Answers:
1. (1) Sum of two consecutive numbers of the series gives the next number.
2. (1) The series consists of prime numbers.
... The missing number is the next prime number, which is 43.
3. (2) Each number is double the preceding one plus 1.
So, the next number is (255 × 2) +1 = 511
4. (4) The sequence is +6, +6, +8, +8, +10, ---------
So the missing number = 43 + 10 = 53
5. (2) Alternatively we add 3 and subtract 1.
Thus 9 + 3 = 12, 12 - 1 = 11, 11 + 3 =14 and so on.
... the missing number = 13 + 3 = 16
6. (5) The sequence is +1, -2, +3, -4, +5. So 129 is wrong. The correct term should be 128.
7. (4) Each term is four less than the preceding number multiplied by 3. Thus 654 is wrong, the correct term being 650.
8. (4) The sequence is +12, +22, +32, +42, +52, +62. The correct term being 92 instead of 91.
9. (1) Each number in the series is multiplied 2 and the result is increased by 1 to obtain the next number ... 39 is
wrong. The correct term being 31.
10. (5) The numbers are 7 × 8, 8 × 9, 9 × 10, 10 × 11, 11×12, 12 × 13 so 150 is wrong.
11. (1) All the letters of each term are moved five steps forward to obtain the corresponding letters of the next term.
12. (4) The first letters of all the terms are alternate. The second letter of each term is moved one step backward to
obtain the second letter of the successive term. The third letter of each term is moved two steps backward to
obtain the third letter of the subsequent term.
13. (5) The letters in each term are moved four steps backward to obtain the letters of the next term.
14. (1) The first, second and third letters of each term are moved three steps forward, four steps backward and two
steps forward respectively to obtain the corresponding letters of the successive term.
15. (3) Each term in the series consists of three consecutive letters in reverse order. The first letter of each term and the
last letter of the term are the same.
16. (3) The first letters of the terms are alternate. The sequence followed by the numbers is +2, +3, +4, -------The last letter of
each term is three steps ahead of the last letter of the preceding term.
17. (3) The letters in the series are alternate and the numbers indicate their position in the alphabet from the beginning.
18. (5) The first, second, third, fourth and fifth terms are moved one, two, three, four and five steps respectively
forward to obtain the successive terms.
19. (4) The first letters of the terms are in alphabetical order, and so are the second and the third letter.
20. (5) Each term of the series consists of two alternate letters and there is a gap of two letters between the last letter
of each term and the first letter of the next term.
21. (3) The series is bac/bac/bac/bac/bac/bac. Thus the pattern bac is repeated.
22. (2) The series is adbcacbdabcddcbadbcacbda. Here the letters equidistant from the beginning and the end of the
series are the same.
23. (2) The series is acba/acba/acba/acba. Thus, the pattern acba is repeated.
24. (1) The series is abc/cab/bca/abc. Thus the letters are in cyclic order.
25. (3) The series is babb/bbab/bbba/bbbb. Thus, in each sequence, ‘a’ moves one step forward and ‘b’ takes its place
and finally in the fourth sequence, it is eleminated.
This section deals with questions in which series of numbers or letters are given. The term follows a certain pattern throughout.
The candidate is required to recognise this pattern either to complete the given series with the most suitable alternative or
to find the wrong term in the series.
NUMBER SERIES
Eg. 1 Which number would replace the question mark (?) in the series 2, 7, 14, 23, ?, 47
(1) 28 (2) 34 (3) 31 (4) 38 (5) None
Ans: The given sequence is +5, +7, +9, ——
ie. 2+ 5 = 7, 7 + 7 = 14, 14 + 9 = 23
Missing Number = 23 + 11 = 34.
2. Which is the number that should come next in the following series?
4, 6, 12, 14, 28, 30, ——
(1) 32 (2) 64 (3) 62 (4) 60 (5) None
Ans: The given sequence is a combination of two series 4, 12, 28, .... and 6, 14, 30, .... Clearly the number to be
found belongs to the first series. Now the pattern followed is +8, +16, +32.
So, missing number = (28 + 32) = 60
Hence the answer is (4)
3. Find the wrong number in the series.
7, 28, 63, 124, 215, 342
(1) 7 (2) 28 (3) 124 (4) 215 (5) None
Ans: The correct sequence is 23 - 1, 33 - 1, 43 - 1, ...etc.
Here 28 is wrong; so the answer is (2)
ALPHABET SERIES
Alphabet series consists of letters of the alphabet placed in a specific pattern. If you keep in your mind the order of
the letters with their respective numbers it will help you answer the questions quickly.
1 2 3 4 5 6 7 8 9 10 11 12 13
A B C D E F G H I J K L M
26 25 24 23 22 21 20 19 18 17 16 15 14
14 15 16 17 18 19 20 21 22 23 24 25 26
N O P Q R S T U V W X Y Z
13 12 11 10 9 8 7 6 5 4 3 2 1
Eg: 4 What will be the next term in
BKS, DJT, FIU, HHV, ?
(1) IJX (2) IGX (3) JGW (4) IGU (5) JGU
Ans: (3). In each term, the first letter is moved two steps forward, the second letter one step backward and
the third letter one step forward to obtain the corresponding letter of the next term. So, the missing term is JGW.
LETTER SERIES
This type of question usually consists of a series of small letters which follow a certain pattern. However some
letters are missing from the series. These missing letters are then given in a proper sequence as one of the
alternatives. The candidate is required to choose this alternative as the answer.
Eg: 5. aab - aaa - bba -
(1) baa (2) abb (3) bab (4) aab (5) bbb
1. The first blank space should be filled in by ‘b’ so that we have two a’s followed by two bs.
2. The second blank space should be fiiled in either by ‘a’. So that we have four as followed by two bs or by ‘b’.
So that we have three as followed by three bs.
3. The last space must be filled in by ‘a’.
4. Thus we have two possible answers - ‘baa’ and ‘bba’. But only ‘baa’ appears in the alternatives. So the answer
is (1).
5. In case we had both the possible answers in the alternatives, we should choose the one that forms a more
prominent pattern, which is aabb/aaabbb/aa. and our answer would have been ‘bba’.
Speed Developing Practice Test No. 6
Directions: In each of the following questions a number series is given with one term missing. Choose the correct
alternative that will continue the same pattern and fill in the blank spaces.
1. 4, 9, 13, 22, 35, ——
(1) 57 (2) 70 (3) 63
(4) 75 (5) None of these
2. 11, 13, 17, 19, 23, 29, 31, 37, 41, ——
(1) 43 (2) 47 (3) 51
(4) 53 (5) None of these
3. 15, 31, 63, 127, 255, ——
(1) 513 (2) 511 (3) 517
(4) 523 (5) None of these
4. 5, 11, 17, 25, 33, 43, ——
(1) 49 (2) 51 (3) 52
(4) 53 (5) None of these
5. 9, 12, 11, 14, 13, ——, 15
(1) 12 (2) 16 (3) 10
(4) 17 (5) None of these
Directions: In each of the following questions, one term in the number series is wrong. Find the wrong term.
6. 125, 126, 124, 127, 123, 129
(1) 123 (2) 124 (3) 126
(4) 127 (5) 129
7. 10, 26, 74, 218, 654, 1946, 5834
(1) 26 (2) 74 (3) 218
(4) 654 (5) 1946
8. 1, 2, 6, 15, 31, 56, 91
(1) 31 (2) 15 (3) 56
(4) 91 (5) 2
9. 3, 7, 15, 39, 63, 127, 255, 511
(1) 39 (2) 15 (3) 7
(4) 63 (5) 127
10. 56, 72, 90, 110, 132, 150
(1) 72 (2) 90 (3) 110
(4) 132 (5) 150
Directions: In each of the following questions, various terms of a letter series are given with one term missing. Choose the missing term out of the given alternatives.
11. cmw, hrb, ——, rbl, wgq, blv
(1) mwg (2) lvf (3) lwg
(4) mxg (5) wmx
12. DKY FJW HIU JHS ——
(1) KGR (2) LFQ (3) KFR
(4) LGQ (5) None of these
13. —— siy oeu kaq gwm csi
(1) wne (2) wnb (3) vne
(4) vme (5) None of these
14. BXJ ETL HPN KLP ——
(1) NHR (2) MHQ (3) MIP
(4) NIR (5) None of these
15. QPO, SRQ, UTS, WVU, ——
(1) XVZ (2) ZYA (3) YXW
(4) VWX (5) AZY
16. P3C, R5F, T8I, V12L, ——
(1) Y17O (2) X17M (3) X17O
(4) X16O (5) None of these
17. D-4, F-6, H-8, J-10, ——, ——
(1) K-12, M-13 (2) L-12, M-14 (3) L-12, N-14
(4) K-12, M-14 (5) K-12, N-14
18. G, H, J, M, ——, V
(1) T (2) S (3) R
(4) U (5) Q
19. OTE PUF QVG RWH ——
(1) SYJ (2) TXI (3) SXJ
(4) SXI (5) QWD
20. BD GI LN QS ——
(1) TV (2) VW (3) WX
(4) WY (5) VX
Directions: In each of the following letter series, some of the letters are missing which are given in that order as one of
the alternatives below it. Choose the correct alternative.
21. ba-ba - bac - acb - cbac
(1) aacb (2) bbca (3) ccba
(4) cbac (5) None of these
22. adb - ac - da - cddcb - dbc - cbda
(1) bccba (2) cbbaa (3) ccbba
(4) bbcad (5) None of these
23. a - ba - cbaac - aa - ba
(1) ccbb (2) cabc (3) cbcb
(4) bbcc (5) None of these
24. - bc - - b - aabc
(1) acac (2) babc (3) abab
(4) aacc (5) None of these
25. b - b - bb - - bbb - bb - b
(1) bbbbba (2) bbaaab (3) ababab
(4) aabaab
Answers:
1. (1) 2. (1) 3. (2) 4. (4) 5. (2) 6. (5) 7. (4) 8. (4) 9. (1) 10. (5) 11.
(1) 12. (4) 13. (5) 14. (1) 15. (3) 16. (3) 17. (3) 18. (5) 19. (4) 20. (5) 21. (3)
22. (2) 23. (2) 24. (1) 25. (3)
Explanatory Answers:
1. (1) Sum of two consecutive numbers of the series gives the next number.
2. (1) The series consists of prime numbers.
... The missing number is the next prime number, which is 43.
3. (2) Each number is double the preceding one plus 1.
So, the next number is (255 × 2) +1 = 511
4. (4) The sequence is +6, +6, +8, +8, +10, ---------
So the missing number = 43 + 10 = 53
5. (2) Alternatively we add 3 and subtract 1.
Thus 9 + 3 = 12, 12 - 1 = 11, 11 + 3 =14 and so on.
... the missing number = 13 + 3 = 16
6. (5) The sequence is +1, -2, +3, -4, +5. So 129 is wrong. The correct term should be 128.
7. (4) Each term is four less than the preceding number multiplied by 3. Thus 654 is wrong, the correct term being 650.
8. (4) The sequence is +12, +22, +32, +42, +52, +62. The correct term being 92 instead of 91.
9. (1) Each number in the series is multiplied 2 and the result is increased by 1 to obtain the next number ... 39 is
wrong. The correct term being 31.
10. (5) The numbers are 7 × 8, 8 × 9, 9 × 10, 10 × 11, 11×12, 12 × 13 so 150 is wrong.
11. (1) All the letters of each term are moved five steps forward to obtain the corresponding letters of the next term.
12. (4) The first letters of all the terms are alternate. The second letter of each term is moved one step backward to
obtain the second letter of the successive term. The third letter of each term is moved two steps backward to
obtain the third letter of the subsequent term.
13. (5) The letters in each term are moved four steps backward to obtain the letters of the next term.
14. (1) The first, second and third letters of each term are moved three steps forward, four steps backward and two
steps forward respectively to obtain the corresponding letters of the successive term.
15. (3) Each term in the series consists of three consecutive letters in reverse order. The first letter of each term and the
last letter of the term are the same.
16. (3) The first letters of the terms are alternate. The sequence followed by the numbers is +2, +3, +4, -------The last letter of
each term is three steps ahead of the last letter of the preceding term.
17. (3) The letters in the series are alternate and the numbers indicate their position in the alphabet from the beginning.
18. (5) The first, second, third, fourth and fifth terms are moved one, two, three, four and five steps respectively
forward to obtain the successive terms.
19. (4) The first letters of the terms are in alphabetical order, and so are the second and the third letter.
20. (5) Each term of the series consists of two alternate letters and there is a gap of two letters between the last letter
of each term and the first letter of the next term.
21. (3) The series is bac/bac/bac/bac/bac/bac. Thus the pattern bac is repeated.
22. (2) The series is adbcacbdabcddcbadbcacbda. Here the letters equidistant from the beginning and the end of the
series are the same.
23. (2) The series is acba/acba/acba/acba. Thus, the pattern acba is repeated.
24. (1) The series is abc/cab/bca/abc. Thus the letters are in cyclic order.
25. (3) The series is babb/bbab/bbba/bbbb. Thus, in each sequence, ‘a’ moves one step forward and ‘b’ takes its place
and finally in the fourth sequence, it is eleminated.
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