Explanation / Important formulas:
Series completion section deals with questions in which series of numbers are given, which are generally called as terms of the series. These terms follow a certain pattern throughout.
The candidate is required to recognize this pattern and either complete the given series with the most suitable alternative or find wrong in the series.
 Number series tests present numerical sequences that follow a logical rule which is based on elementary arithmetic.
 The difficulty level of these questions can increase in two ways; first, the logic behind the sequence becomes less trivial and demands attention and creativity; second, the missing number can be positioned at an early stage, thus preventing you from deciphering the hidden rule by looking only at the previous numbers in the sequence.
Instructions to take Aptitude Test
 Click on start to start taking the test.
 Click on the option (A, B, C or D) to figure out the right answer.
 You can answer multiple times till you get the right answer.
 Once you get the right answer, explanations (if any) for the same will be showcased down.
 On click of list, you get to see total no of questions, no of questions you answered and no of questions pending to answer.
 On click of question number you will go to that particular question.
 On click of END your test will end.
 On click of ‘Get Results’ you will get to see correct answer for each questions.
Series Completion  Test
Series Completion  Question and Answers
Please wait while the activity loads.
If this activity does not load, try refreshing your browser. Also, this page requires javascript. Please visit using a browser with javascript enabled.
If this activity does not load, try refreshing your browser. Also, this page requires javascript. Please visit using a browser with javascript enabled.
If loading fails, click here to try again
Start
Congratulations  you have completed Series Completion  Question and Answers.
You scored %%SCORE%% out of %%TOTAL%%.
Your performance has been rated as %%RATING%%
Your answers are highlighted below.
Question 1

120, 99, 80, 63, 48, ?
A

35

B

38

C

39

D

40

Question 1 Explanation:
The pattern is  21,  19,  17,  15,.....
So, missing term = 48  13 = 35.
So, missing term = 48  13 = 35.
Question 2

589654237, 89654237, 8965423, 965423, ?
A

58965

B

65423

C

89654

D

96542

Question 2 Explanation:
The digits are removed one by one from the beginning and the end in order alternately. So as to obtain the subsequent terms of the series.
Question 3

3, 10, 101,?
A

10101

B

10201

C

10202

D

11012

Question 3 Explanation:
Each term in the series is obtained by adding 1 to the square of the preceding term.
So, missing term = 101^{2} + 1 = 10202.
So, missing term = 101^{2} + 1 = 10202.
Question 4

In the series 2, 6, 18, 54, ...... what will be the 8th term ?
A

4370

B

4374

C

7443

D

7434

Question 4 Explanation:
Clearly, 2 x 3 = 6, 6 x 3 = 18, 18 x 3 = 54,....
.
So, the series is a G.P. in which a = 2, r = 3.
Therefore 8th term = ar81 = ar7 = 2 x 37 = (2 x 2187) = 4374.
.
So, the series is a G.P. in which a = 2, r = 3.
Therefore 8th term = ar81 = ar7 = 2 x 37 = (2 x 2187) = 4374.
Question 5

125,80,45,20,?
A

5

B

8

C

10

D

12

Question 5 Explanation:
The pattern is  45,  35,  25, .....
So, missing term = 20  15 = 5.
So, missing term = 20  15 = 5.
Question 6

1, 2, 3, 6, 9, 18, ?, 54
A

18

B

27

C

36

D

81

Question 6 Explanation:
The pattern is x 2, x 3/2, x 2, x 3/2, x 2,.....
So, missing term = 18 x 3/2 = 27.
So, missing term = 18 x 3/2 = 27.
Question 7

6, 13, 25, 51, 101, ?
A

201

B

202

C

203

D

205

Question 7 Explanation:
The pattern is x 2 + 1, x 2  1, x 2 + 1, x 2  1,.....
So, missing term = 101 x 2 + 1 = 203.
So, missing term = 101 x 2 + 1 = 203.
Question 8

5,6,9, 15, ?, 40
A

21

B

25

C

27

D

33

Question 8 Explanation:
The pattern is + 1, + 3, + 6,....., i.e. + 1, + (1, + 2), + (1 + 2 + 3),.....
So, missing term = 15 + (1 + 2 + 3 + 4) = 25.
So, missing term = 15 + (1 + 2 + 3 + 4) = 25.
Question 9

1, 3, 4, 8, 15, 27, ?
A

37

B

44

C

50

D

55

Question 9 Explanation:
The sum of any three consecutive terms of the series gives the next term.
So, missing number = 8 + 15 + 27 = 50.
So, missing number = 8 + 15 + 27 = 50.
Question 10

3, 4, 7, 7, 13, 13, 21, 22, 31, 34, ?
A

42

B

43

C

52

D

53

Question 10 Explanation:
The given sequence is a combination of two series :
I. 3, 7, 13, 21, 31, ? and II. 4, 7, 13, 22, 34
The pattern in I is + 4, + 6, + 8, + 10,.....
The pattern in II is + 3, + 6, + 9, + 12,.....
So, missing term = 31 + 12 = 43.
I. 3, 7, 13, 21, 31, ? and II. 4, 7, 13, 22, 34
The pattern in I is + 4, + 6, + 8, + 10,.....
The pattern in II is + 3, + 6, + 9, + 12,.....
So, missing term = 31 + 12 = 43.
Question 11

198, 194, 185, 169, ?
A

92

B

112

C

136

D

144

Question 11 Explanation:
The pattern is  4,  9,  16,.....i.e.  22,  32,  42,.....
So, missing pattern = 169  52 = 169  25 = 144.
So, missing pattern = 169  52 = 169  25 = 144.
Question 12

6, 12, 21, ?, 48
A

33

B

38

C

40

D

45

Question 12 Explanation:
The pattern is + 6, + 9, + 12, + 15, .....
So, missing term = 21 + 12 = 33.
So, missing term = 21 + 12 = 33.
Question 13

Which term of the series 5, 10, 20, 40, ..... is 1280?
A

10th

B

9th

C

8th

D

None of these

Question 13 Explanation:
Clearly, 5 x 2 = 10, 10 x 2 = 20, 20 x 2 = 40,.....
So, the series is a G.P. in which a = 5 and r = 2.
Let 1280 be the rath term of the series.
Then, 5x2n1 = 1280 2n1 = 256 = 28 n  1 = 8 n = 9.
So, the series is a G.P. in which a = 5 and r = 2.
Let 1280 be the rath term of the series.
Then, 5x2n1 = 1280 2n1 = 256 = 28 n  1 = 8 n = 9.
Question 14

2, 5, 9, ?, 20, 27
A

14

B

16

C

18

D

24

Question 14 Explanation:
The pattern is + 3, + 4, + 5, + 6,.....
So, missing term = 9 + 5 = 14.
So, missing term = 9 + 5 = 14.
Question 15

2, 3, 3, 5, 10, 13, ?, 43, 172, 177
A

23

B

38

C

39

D

40

Question 15 Explanation:
The pattern is + 1, x 1, + 2, x 2, + 3, x 3, + 4, x 4, + 5.
So, missing term = 13 x 3 = 39.
So, missing term = 13 x 3 = 39.
Question 16

9, 27, 31, 155, 161, 1127, ?
A

316

B

1135

C

1288

D

2254

Question 16 Explanation:
The pattern is x 3, + 4, x 5, + 6, x 7,.....
So, missing term = 1127 + 8 = 1135.
So, missing term = 1127 + 8 = 1135.
Question 17

2, 1, 2, 4, 4, 5, 6, 7, 8, 8, 10, 11, ?
A

9

B

10

C

11

D

12

Question 17 Explanation:
The given sequence is a combination of three series :
I. 1st, 4th, 7th, 10th, 13th terms i.e. 2, 4, 6, 8, ?
II. 2nd, 5th, 8th, 11th terms i.e. 1, 4, 7, 10
III. 3rd, 6th, 9th, 12th terms i.e. 2, 5, 8, 11
Clearly, I consists of consecutive even numbers. So, the missing term is 10.
I. 1st, 4th, 7th, 10th, 13th terms i.e. 2, 4, 6, 8, ?
II. 2nd, 5th, 8th, 11th terms i.e. 1, 4, 7, 10
III. 3rd, 6th, 9th, 12th terms i.e. 2, 5, 8, 11
Clearly, I consists of consecutive even numbers. So, the missing term is 10.
Question 18

Which of the following will not be a number of the series 1, 8, 27, 64, 125,.....?
A

256

B

512

C

729

D

1000

Question 18 Explanation:
The given series consists of cubes of natural numbers only. 256 is not the cube of
any natural number.
any natural number.
Question 19

13, 32, 24, 43, 35, ?, 46, 65, 57, 76
A

45

B

52

C

54

D

55

Question 19 Explanation:
The given sequence is a combination of two series:
I. 13, 24, 35, 46, 57 and II. 32, 43, ?, 65, 76
The pattern in both I and II is + 11. So, missing term = 43 + 11 = 54.
I. 13, 24, 35, 46, 57 and II. 32, 43, ?, 65, 76
The pattern in both I and II is + 11. So, missing term = 43 + 11 = 54.
Question 20

3, 15, ?, 63, 99, 143
A

27

B

35

C

45

D

56

Question 20 Explanation:
The terms of the given series are (22  1), (42  1),....., (82  1), (102  1), (122  1).
So, missing term = (62  1)  (36  1) = 35.
So, missing term = (62  1)  (36  1) = 35.
Question 21

90, 180, 12, 50, 100, 200, ?, 3, 50, 4, 25, 2, 6, 30, 3
A

150

B

175

C

225

D

250

Question 21 Explanation:
Clearly, 90 = 30 x 3, 180 = 6 x 30, 12 = 2 x 6, 50 = 25 x 2, 100 = 4 x 25, 200 = 50 x 4.
So, missing term = 3 x 50 = 150.
So, missing term = 3 x 50 = 150.
Question 22

48, 24, 96, 48, 192, ?
A

76

B

90

C

96

D

98

Question 22 Explanation:
The pattern is Ã· 2, x 4, Ã· 2, x 4, .....
So, missing term = 192 Ã· 2 = 96.
So, missing term = 192 Ã· 2 = 96.
Question 23

2,15,41,80,?
A

111

B

120

C

121

D

132

Question 23 Explanation:
The pattern is + 13, + 26, + 39,.....
So, missing term = 80 + 52 = 132.
So, missing term = 80 + 52 = 132.
Question 24

6, 11, 21, 36, 56, ?
A

42

B

51

C

81

D

91

Question 24 Explanation:
The pattern is + 5, + 10, + 15, + 20, ...
So, missing term = 56 + 25 = 81.
So, missing term = 56 + 25 = 81.
Question 25

563, 647, 479, 815, ?
A

672

B

386

C

279

D

143

Question 25 Explanation:
The pattern is + 84,  168, + 336,.....i.e. + 84,  (84 x 2), + (84 x 22), .....
So, missing term = 815  (84 x 23) = 815  672 = 143.
So, missing term = 815  (84 x 23) = 815  672 = 143.
Question 26

13, 35, 57, 79, 911, ?
A

1110

B

1112

C

1113

D

1315

Question 26 Explanation:
The terms of the given series are numbers formed by joining together consecutive
odd numbers in order i.e. 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11, .....
So, missing term = number formed by joining 11 and 13 = 1113.
odd numbers in order i.e. 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11, .....
So, missing term = number formed by joining 11 and 13 = 1113.
Question 27

1, 4, 10, 22, 46, ?
A

64

B

86

C

94

D

122

Question 27 Explanation:
The pattern is + 3, + 6, + 12, + 24,.....
So, missing term = 46 + 48 = 94.
So, missing term = 46 + 48 = 94.
Question 28

66, 36, 18, ?
A

3

B

6

C

8

D

9

Question 28 Explanation:
Each term in the series is the product of the digits of the preceding term.
So, missing term = 1 x 8 = 8.
So, missing term = 1 x 8 = 8.
Question 29

In the series 3, 9, 15, ...... what will be the 21st term?.
A

117

B

121

C

123

D

129

Question 29 Explanation:
Clearly, 3 + 6 = 9, 9 + 6 = 15,.....
So, the series is an A.P. in which a = 3 and d = 6.
Therefore 21st term = a + (21  1) d = a + 20d = 3 + 20 x 6 = 123.
So, the series is an A.P. in which a = 3 and d = 6.
Therefore 21st term = a + (21  1) d = a + 20d = 3 + 20 x 6 = 123.
Question 30

28, 33, 31, 36, ?, 39
A

32

B

34

C

38

D

40

Question 30 Explanation:
The pattern is + 5,  2, + 5,  2,.....
So, missing term = 36  2 = 34.
So, missing term = 36  2 = 34.
Question 31

1, 9, 25, 49, ?, 121
A

64

B

81

C

91

D

100

Question 31 Explanation:
The given series consists of squares of consecutive odd numbers
i.e. 12, 32, 52, 72,.....
So, missing term = 92 = 81.
i.e. 12, 32, 52, 72,.....
So, missing term = 92 = 81.
Question 32

2,2,5, 13,28,?
A

49

B

50

C

51

D

52

Question 32 Explanation:
The pattern is + 0, + 3, + 8, + 15, ..... i.e. + (l2  1), + (22  1), + (32  1), + (42  1), .....
So, missing term = 28 + (52  1) = 28 + 24 = 52.
So, missing term = 28 + (52  1) = 28 + 24 = 52.
Question 33

0, 2, 8, 14, ?, 34
A

20

B

23

C

24

D

25

Question 33 Explanation:
The pattern is + 2, + 6, + 6, + 10, + 10,.....
So, missing term = 14 + 10 = 24.
So, missing term = 14 + 10 = 24.
Question 34

In the series 10, 17, 24, 31, 38,.....which of the following will be a number of the series ?
A

48

B

346

C

574

D

1003

Question 34 Explanation:
The given series consists of numbers each of which, on dividing by 7, leaves a
remainder 3. No other number except 346 satisfies the property.
remainder 3. No other number except 346 satisfies the property.
Question 35

240, ?, 120, 40, 10, 2
A

180

B

240

C

420

D

480

Question 35 Explanation:
The pattern is ÷ 1, ÷ 2, ÷ 3, ÷ 4, ÷ 5.
So, missing term = 240 ÷ 1 = 240
So, missing term = 240 ÷ 1 = 240
Question 36

2,3,8,27, 112,?
A

226

B

339

C

452

D

565

Question 36 Explanation:
The pattern is x 1 + 1, x 2 + 2, x 3 + 3, x 4 + 4,.....
So, missing term = 112 x 5 + 5 = 565.
So, missing term = 112 x 5 + 5 = 565.
Question 37

6, 17, 39, 72, ?
A

83

B

94

C

116

D

127

Question 37 Explanation:
The pattern is + 11, + 22, + 33, .....
So, missing term = 72 + 44 = 116.
So, missing term = 72 + 44 = 116.
Question 38

20, 20, 19, 16, 17, 13, 14, 11, ?, ?
A

10, 10

B

10, 11

C

13, 14

D

13, 16

Question 38 Explanation:
Let the missing terms of the series be x1 and x2.
Thus, the sequence 20, 20, 19, 16, 17, 13, 14, 11, xv x2 is a combination of two series :
I. 20, 19, 17, 14, x1 and II. 20, 16, 13, 11, x2
The pattern in I is  1,  2,  3,......So, missing term, x1 = 14  4 = 10.
The pattern in II is  4,  3,  2,......So, missing term, x2 = 11  1 = 10.
Thus, the sequence 20, 20, 19, 16, 17, 13, 14, 11, xv x2 is a combination of two series :
I. 20, 19, 17, 14, x1 and II. 20, 16, 13, 11, x2
The pattern in I is  1,  2,  3,......So, missing term, x1 = 14  4 = 10.
The pattern in II is  4,  3,  2,......So, missing term, x2 = 11  1 = 10.
Question 39

10, 100, 200, 310, ?
A

400

B

410

C

420

D

430

Question 39 Explanation:
The pattern is + 90 + 100, + 110,.....
So, missing term = 310 + 120 = 430.
So, missing term = 310 + 120 = 430.
Question 40

11, 10, ?, 100, 1001, 1000, 10001
A

101

B

110

C

111

D

None of these

Question 40 Explanation:
The pattern is  1, x 10 + 1,  1, x 10 + 1,  1, x 10 + 1, .....
So, missing term = 10 x 10 + 1 = 101.
So, missing term = 10 x 10 + 1 = 101.
Question 41

2, 7, 27, 107, 427, ?
A

1262

B

1707

C

4027

D

4207

Question 41 Explanation:
The pattern is + 5, + 20, + 80, + 320, ...... i.e. + (5 x 12), + (5 x 22), + (5 x 42), + (5 x 82),.....
So, missing term = 427 + (5 x 162) = 427 + 1280 = 1707.
So, missing term = 427 + (5 x 162) = 427 + 1280 = 1707.
Question 42

Complete the series 2,2,5, 13,28,...
A

50

B

51

C

52

D

53

Question 42 Explanation:
+1^21, +2^21, +3^21,+4^21
5^21 = 28 + 24
= 52
5^21 = 28 + 24
= 52
Question 43

Which number would replace the question mark in series
7,12,19,?,39
7,12,19,?,39
A

24

B

28

C

31

D

33

Question 43 Explanation:
Pattern is , +5, +7, +9
Missing Number = 19+9 = 28
Missing Number = 19+9 = 28
Once you are finished, click the button below. Any items you have not completed will be marked incorrect.
Get Results
Get Results
There are 43 questions to complete.
You have completed
questions
question
Your score is
Correct
Wrong
PartialCredit
You have not finished your quiz. If you leave this page, your progress will be lost.
Correct Answer
You Selected
Not Attempted
Final Score on Quiz
Attempted Questions Correct
Attempted Questions Wrong
Questions Not Attempted
Total Questions on Quiz
Question Details
Results
Date
Score
Hint
Time allowed
minutes
seconds
Time used
Answer Choice(s) Selected
Question Text
All done
Need more practice!
Keep trying!
Not bad!
Good work!
Perfect!