Direction (Q.1-10): What should come at the place of question mark (?) in the following number series?

Direction (Q.1-10): What should come at the place of question mark (?) in the following number series?

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**Q.1 221, 109, 53, 25, 11, ? **

**A.**6

**B.**4

**C.**8

**D.**10

**E.**15

**Ans. B.**

**Explanation:**

(221-3)÷2 = 109

(109-3)÷2 = 53

(53-3)÷2 = 25

(25-3)÷2 = 11

(11-3)÷2 = 4

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** Q.2 0.5, 12, 52, 106, 107, ? **

**A.**40

**B.**45

**C.**50

**D.**54

**E.**None of these

**Ans. D.**

**Explanation:**

0.5×8+8 = 12

12×4+4 = 52

52×2+2 = 106

106×1+1 = 107

107×.5+.5 = 54

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**Q.3 39, 31, 41, 29, 43, ? **

**A.**20

**B.**25

**C.**27

**D.**30

**E.**29

**Ans. C.**

**Explanation:**

This is the mixture of 2 series:

39+2 = 41

41+2 = 43

31-2 = 29

29-2 = 27

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** Q.4 3, 5, 13, 49, ? , 1441 **

**A.**300

**B.**295

**C.**325

**D**. 245

**E.**241

**Ans. E.**

**Explanation:**

3×2-1 = 5

5×3-2 = 13

13×4-3 = 49

49×5-4 = 241

242×6-5 = 1441

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** Q.5 481, 477, 467, 439, 357, ? **

**A.**110

**B.**113

**C.**115

**D.**120

**E.**125

**Ans. B.**

**Explanation:**

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**Q.6 17, 31, 15, 33, 13, ? **

**A.**39

**B.**37

**C**. 30

**D.**35

**E.**None of these

**Ans. D.**

**Explanation:**

This is the mixture of 2 series:

17-2 = 15

15-2 = 13

31+2 = 33

33+2 = 35

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** Q.7 0.5, 2, 8, 35, ?, 1079 **

**A.**160

**B.**179

**C.**185

**D.**175

**E.**182

**Ans. B.**

**Explanation:**

0.5×2+1 = 2

2×3+2 = 8

8×4+3 = 35

35×5+4 = 179

179×6+5 = 1079

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** Q.8 167, 164, 159, 150, ?, 100 **

**A.**129

**B.**122

**C.**130

**D.**125

**E.**133

**Ans. E.**

**Explanation:**

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** Q.9 2, 8, 28, 54, 53, ? **

**A.**26

**B.**24

**C.**28

**D.**30

**E.**25

**Ans. A.**

**Explanation:**

2×8-8 = 8

8×4-4 = 28

28×2-2 = 54

54×1-1 = 53

53×.5-.5 = 26

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**Q.10 973, 325, 109, 37, 13, ? **

**A.**9

**B.**3

**C.**5

**D.**8

**E.**10

**Ans. C.**

**Explanation:**

973+2÷3 = 325

325+2÷3 = 109

109+2÷3 = 37

37+2÷3 = 13

13+2÷3 = 5