# Number Series (Previous Year Questions )test -1

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Ashwin
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Quizzes Created: 6 | Total Attempts: 646
Questions: 15 | Attempts: 146

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• 1.

### 14, 8, 7, 11.5, 22, ?

• A.

54

• B.

64

• C.

62

• D.

58

• E.

56

E. 56
Explanation
14*0.5 + 1 = 7+1= 8
8*1 - 1 = 8-1 = 7
7*1.5 + 1 = 10.5 + 1 = 11.5
11.5*2 - 1 = 23 - 1 = 22
22*2.5 +1 = 55+1 =56

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• 2.

### 8, 14, 25, 46, 82, ?

• A.

132

• B.

130

• C.

138

• D.

128

• E.

142

C. 138
Explanation
14 - 8 = 6
25 - 14 =11
46 - 25 = 21
82 - 46 = 36

Now take the difference of difference
11 - 6 = 5
21 - 11 = 10
36 - 21 = 15

The next term will be 20. The difference will be 36 + 20 = 56.

The required term is 82 + 56 = 138.

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• 3.

### 13, 14, 30, 93, ?, 1885

• A.

358

• B.

336

• C.

364

• D.

376

D. 376
Explanation
13*1 + 1 = 14
14*2 +2 = 28+2 = 30
30*3 + 3 = 90+3 =93
93*4 + 4 = 372+4 = 376

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• 4.

### 65, 70, 63, 74, 61, ?

• A.

78

• B.

52

• C.

72

• D.

58

A. 78
Explanation
We can note that consecutive prime numbers are either added or subtracted starting from 5.

65+5 = 70
70-7 = 63
63+11 = 74
74-13 = 61
61+17 = 78

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• 5.

### 11, 20, 38, 74, ?

• A.

146

• B.

154

• C.

128

• D.

136

A. 146
Explanation
11*2 - 2 = 22-2 =20
20*2 - 2= 40-2 = 38
38*2 - 2= 76 - 2 = 74
74*2 - 2 = 148-2 = 146

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• 6.

### 15, 21, 38, 65, 101, ?

• A.

124

• B.

145

• C.

136

• D.

158

B. 145
Explanation
21 - 15 = 6
38 - 21 = 17
65 - 38 = 27
101 - 65 = 36
Now, let us take the difference of difference.
17 - 6 = 11
27 - 17 = 10
36 - 27 = 9
Continuing the sequence, we get the next term as 36+8 = 44
101 + 44 = 145.

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• 7.

### 24, 28, 19, 35, 10, ?

• A.

26

• B.

36

• C.

16

• D.

46

D. 46
Explanation
24 + 4 = 28
28 - 9 = 19
19 + 16 = 35
35 - 25 = 10
10 + 36 = 46

The pattern is +4, -9, +16, -25, +36 (Squares with alternate sign)

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• 8.

### 7, 16, 45, 184, 915, ?

• A.

2092

• B.

5496

• C.

1048

• D.

4038

B. 5496
Explanation
7*2 + 2= 14+2 = 16
16*3 - 3 = 48 - 3 = 45
45*4 + 4 = 180+4 = 184
184*5 - 5 = 920 - 5 = 915.
915*6 + 6 = 5490+ 6 = 5496.

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• 9.

### 9, 5, 6, 10.5, 23, ?

• A.

85

• B.

60

• C.

78

• D.

49

B. 60
Explanation
9*0.5 + 0.5 = 4.5 + 0.5 = 5
5*1 +1 = 5+1 =6
6*1.5 + 1.5 = 9+1.5 =10.5
10.5*2 + 2 = 21+2 = 23
23*2.5 + 2.5 = 57.5+2.5 = 60.

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• 10.

### 59, 66, 80, 108, ?, 276

• A.

150

• B.

125

• C.

164

• D.

132

C. 164
Explanation
59 + 7 = 66
66 + 14 = 80
80+ 28 = 108
108 + 56 = 164

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• 11.

### 47, 23, 11, 5, 2, ?

• A.

0.2

• B.

0.5

• C.

1

• D.

1.5

B. 0.5
Explanation
47*0.5 - 0.5= 23.5 - 0.5 = 23
23*0.5 - 0.5 = 11.5 - 0.5 =11
11*0.5 - 0.5 = 5.5 - 0.5 = 5
5*0.5 - 0.5 = 2.5 - 0.5 = 2
2*0.5 - 0.5 = 1 - 0.5 = 0.5

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• 12.

### 1, 2, 6, 21, 88, ?

• A.

445

• B.

615

• C.

216

• D.

539

A. 445
Explanation
1*1 + 1 = 2
2*2 + 2 = 6
6*3 + 3 = 21
21*4 + 4 = 88
88*5 + 5 = 445

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• 13.

### 9, 10.8, 14.4, 21.6, ?, 64.8

• A.

36

• B.

44

• C.

34

• D.

37.6

A. 36
Explanation
9 + 1.8 = 10.8
10.8 + (2*1.8) = 10.8 + 3.6 = 14.4
14.4 + (2*3.6) = 14.4+7.2 = 21.6
21.6 + (2*7.2) = 21.6 + 14.4 = 36

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• 14.

### 6, 5, 8, 21, 80, ?

• A.

268

• B.

192

• C.

395

• D.

364

C. 395
Explanation
6*1 -1 = 5
5*2 - 2 = 10-2 =8
8*3 - 3 = 24-3 = 21
21*4-4 = 84-4 = 80
80*5-5 = 395

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• 15.

### 13, 6, 5, 6, 10, ?

• A.

19

• B.

25

• C.

22.5

• D.

17.5

C. 22.5
Explanation
13*0.5 - 0.5 = 6.5-0.5 = 6
6*1 - 1 = 6-1 = 5
5*1.5 - 1.5 = 7.5 - 1.5 = 6
6*2 - 2 = 12-2 = 10
10*2.5 - 2.5 = 25-2.5 =22.5

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