Q1. Find the next number: 6, 13, 20, 27, 34, ?
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Answer: C. 41
Each term increases by 7. 34 + 7 = 41.
Number Series Questions for SSC CGL (with Answers)
115 Number Series MCQs from the General Intelligence & Reasoning section, with answers and short explanations.
Score: 0 / 0
Q2. Find the next number: 4, 12, 36, 108, 324, ?
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Answer: B. 972
Each term is multiplied by 3. 324 × 3 = 972.
Q3. Find the next number: 25, 36, 49, 64, 81, ?
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Answer: A. 100
The terms are n² for n = 5, 6, … so the next is 10² = 100.
Q4. Find the next number: 10, 18, 26, 34, 42, ?
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Answer: A. 50
Each term increases by 8. 42 + 8 = 50.
Q5. Find the next number: 5, 15, 45, 135, 405, ?
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Answer: B. 1215
Each term is multiplied by 3. 405 × 3 = 1215.
Q6. Find the next number: 4, 9, 16, 25, 36, ?
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Answer: A. 49
The terms are n² for n = 2, 3, … so the next is 7² = 49.
Q7. Find the next number in the series: 5, 15, 45, 135, 405, ?
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Answer: D. 1215
Each term is multiplied by 3: 405 × 3 = 1215.
Q8. Find the next number in the series: 25, 40, 55, 70, 85, ?
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Answer: B. 100
Each term increases by 15: 85 + 15 = 100.
Q9. Find the next number in the series: 3, 6, 12, 24, 48, ?
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Answer: B. 96
Each term is multiplied by 2: 48 × 2 = 96.
Q10. Find the next number in the series: 31, 36, 41, 46, 51, ?
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Answer: C. 56
Each term increases by 5: 51 + 5 = 56.
Q11. Find the next number in the series: 2, 6, 18, 54, 162, ?
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Answer: C. 486
Each term is multiplied by 3: 162 × 3 = 486.
Q12. Find the next number in the series: 6, 18, 54, 162, 486, ?
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Answer: A. 1458
Each term is multiplied by 3: 486 × 3 = 1458.
Q13. Find the next number in the series: 7, 21, 63, 189, 567, ?
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Answer: A. 1701
Each term is multiplied by 3: 567 × 3 = 1701.
Q14. Find the next number in the series: 4, 8, 16, 32, 64, ?
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Answer: A. 128
Each term is multiplied by 2: 64 × 2 = 128.
Q15. Find the next number in the series: 28, 35, 42, 49, 56, ?
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Answer: D. 63
Each term increases by 7: 56 + 7 = 63.
Q16. Find the next number in the series: 6, 12, 24, 48, 96, ?
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Answer: B. 192
Each term is multiplied by 2: 96 × 2 = 192.
Q17. Find the next number in the series: 36, 50, 64, 78, 92, ?
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Answer: A. 106
Each term increases by 14: 92 + 14 = 106.
Q18. Find the next number in the series: 21, 27, 33, 39, 45, ?
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Answer: C. 51
Each term increases by 6: 45 + 6 = 51.
Q19. Find the wrong number in the series: 6, 13, 18, 27, 34, 41, 48
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Answer: B. 18
Rule: add 7. The term should be 20, not 18.
Q20. Find the next number in the series: 7, 14, 28, 56, 112, ?
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Answer: A. 224
Each term is multiplied by 2: 112 × 2 = 224.
Q21. Find the wrong number in the series: 4, 8, 19, 32, 64, 128, 256
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Answer: C. 19
Rule: multiply by 2. The term should be 16, not 19.
Q22. Find the wrong number in the series: 64, 81, 100, 121, 144, 171, 196
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Answer: D. 171
Rule: squares of 8 to 14. The term should be 169, not 171.
Q23. Find the next number in the series: 20, 33, 46, 59, 72, ?
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Answer: B. 85
Each term increases by 13: 72 + 13 = 85.
Q24. Find the wrong number in the series: 2, 8, 14, 20, 26, 34, 38
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Answer: C. 34
Rule: add 6. The term should be 32, not 34.
Q25. Find the wrong number in the series: 16, 26, 36, 46, 59, 66, 76
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Answer: C. 59
Rule: add 10. The term should be 56, not 59.
Q26. Find the wrong number in the series: 16, 25, 36, 49, 63, 81, 100
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Answer: B. 63
Rule: squares of 4 to 10. The term should be 64, not 63.
Q27. Find the wrong number in the series: 4, 8, 16, 32, 64, 130, 256
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Answer: B. 130
Rule: multiply by 2. The term should be 128, not 130.
Q28. Find the next number in the series: 22, 27, 32, 37, 42, ?
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Answer: C. 47
Each term increases by 5: 42 + 5 = 47.
Q29. Find the wrong number in the series: 6, 11, 16, 23, 26, 31, 36
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Answer: D. 23
Rule: add 5. The term should be 21, not 23.
Q30. Find the wrong number in the series: 9, 16, 25, 36, 50, 64, 81
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Answer: A. 50
Rule: squares of 3 to 9. The term should be 49, not 50.
Q31. Find the wrong number in the series: 3, 6, 12, 24, 48, 94, 192
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Answer: B. 94
Rule: multiply by 2. The term should be 96, not 94.
Q32. Find the next number: 11, 22, 33, 44, 55, ?
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Answer: C. 66
Each term increases by 11. 55 + 11 = 66.
Q33. Find the next number: 2, 6, 18, 54, 162, ?
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Answer: B. 486
Each term is multiplied by 3. 162 × 3 = 486.
Q34. Find the next number: 10, 17, 26, 37, 50, ?
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Answer: D. 65
The terms are n² plus 1 for n = 3, 4, … so the next is 8² plus 1 = 65.
Q35. Find the next number: 19, 30, 41, 52, 63, ?
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Answer: B. 74
Each term increases by 11. 63 + 11 = 74.
Q36. Find the next number: 3, 9, 27, 81, 243, ?
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Answer: A. 729
Each term is multiplied by 3. 243 × 3 = 729.
Q37. Find the next number in the series: 3, 9, 27, 81, 243, ?
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Answer: B. 729
Each term is multiplied by 3: 243 × 3 = 729.
Q38. Find the missing number in the series: 10, 54, 14, ?, 18, 46
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Answer: C. 50
Two alternating series: 10, 14, 18 (+4) and 54, 50, 46 (−4).
Q39. Find the next number in the series: 65, 82, 101, 122, 145, ?
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Answer: B. 170
Terms are n² + 1 for n = 8…13: 13² + 1 = 170.
Q40. Find the missing number in the series: 16, 37, ?, 31, 20, 25
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Answer: B. 18
Two alternating series: 16, 18, 20 (+2) and 37, 31, 25 (−6).
Q41. Find the missing number in the series: 15, 43, 20, ?, 25, 29
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Answer: D. 36
Two alternating series: 15, 20, 25 (+5) and 43, 36, 29 (−7).
Q42. Find the next number in the series: 20, 22, 28, 38, 52, ?
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Answer: A. 70
Differences are 2, 6, 10, 14, 18 (increasing by 4). So 52 + 18 = 70.
Q43. Find the missing number in the series: 6, 30, 9, 24, 12, ?
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Answer: D. 18
Two alternating series: 6, 9, 12 (+3) and 30, 24, 18 (−6).
Q44. Find the missing number in the series: 8, 17, 33, ?, 133, 267
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Answer: C. 67
Pattern: ×2 + 1, ×2 − 1 alternately.
Q45. Find the next number in the series: 16, 20, 28, 40, 56, ?
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Answer: B. 76
Differences are 4, 8, 12, 16, 20 (increasing by 4). So 56 + 20 = 76.
Q46. Find the missing number in the series: 7, 15, 29, 59, 117, ?
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Answer: C. 235
Pattern: ×2 + 1, ×2 − 1 alternately.
Q47. Find the next number in the series: 7, 8, 11, 16, 23, ?
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Answer: C. 32
Differences are 1, 3, 5, 7, 9 (increasing by 2). So 23 + 9 = 32.
Q48. Find the missing number in the series: 3, 39, 8, ?, 13, 31
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Answer: D. 35
Two alternating series: 3, 8, 13 (+5) and 39, 35, 31 (−4).
Q49. Find the missing number in the series: 18, 33, ?, 30, 30, 27
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Answer: A. 24
Two alternating series: 18, 24, 30 (+6) and 33, 30, 27 (−3).
Q50. Find the next number in the series: 59, 61, 67, 71, 73, ?
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Answer: A. 79
These are consecutive prime numbers. Next = 79.
Q51. Find the next number in the series: 26, 37, 50, 65, 82, ?
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Answer: B. 101
Terms are n² + 1 for n = 5…10: 10² + 1 = 101.
Q52. Find the wrong number in the series: 4, 9, 16, 26, 36, 49, 64
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Answer: B. 26
Rule: squares of 2 to 8. The term should be 25, not 26.
Q53. Find the missing number in the series: 1, 3, 5, ?, 21, 43
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Answer: D. 11
Pattern: ×2 + 1, ×2 − 1 alternately.
Q54. Find the next number in the series: 30, 42, 56, 72, 90, ?
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Answer: A. 110
Terms are n(n + 1) for n = 5…10. Next = 110.
Q55. Find the wrong number in the series: 28, 37, 45, 55, 64, 73, 82
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Answer: C. 45
Rule: add 9. The term should be 46, not 45.
Q56. Find the next number in the series: 4, 1, 5, 6, 11, ?
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Answer: C. 17
Each term is the sum of the previous two. Next = 17.
Q57. Find the wrong number in the series: 24, 30, 36, 42, 51, 54, 60
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Answer: D. 51
Rule: add 6. The term should be 48, not 51.
Q58. Find the next number in the series: 35, 48, 63, 80, 99, ?
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Answer: A. 120
Terms are n² − 1 for n = 6…11: 11² − 1 = 120.
Q59. Find the next number in the series: 8, 17, 35, 71, 143, ?
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Answer: D. 287
Each term = previous × 2 + 1. Next = 287.
Q60. Find the missing number in the series: 18, 55, 22, 51, ?, 47
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Answer: B. 26
Two alternating series: 18, 22, 26 (+4) and 55, 51, 47 (−4).
Q61. Find the wrong number in the series: 11, 19, 21, 26, 31, 36, 41
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Answer: A. 19
Rule: add 5. The term should be 16, not 19.
Q62. Find the next number in the series: 12, 20, 30, 42, 56, ?
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Answer: B. 72
Terms are n(n + 1) for n = 3…8. Next = 72.
Q63. Find the wrong number in the series: 9, 16, 24, 36, 49, 64, 81
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Answer: A. 24
Rule: squares of 3 to 9. The term should be 25, not 24.
Q64. Find the next number in the series: 9, 28, 65, 126, 217, ?
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Answer: B. 344
Terms are n³ + 1 for n = 2…7. Next = 344.
Q65. Find the next number in the series: 1, 6, 21, 66, 201, ?
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Answer: B. 606
Each term = previous × 3 + 3. Next = 606.
Q66. Find the next number in the series: 1, 2, 7, 16, 29, ?
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Answer: D. 46
Differences are 1, 5, 9, 13, 17 (increasing by 4). So 29 + 17 = 46.
Q67. Find the wrong number in the series: 3, 6, 12, 24, 48, 99, 192
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Answer: C. 99
Rule: multiply by 2. The term should be 96, not 99.
Q68. Find the missing number in the series: 15, 42, ?, 38, 23, 34
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Answer: C. 19
Two alternating series: 15, 19, 23 (+4) and 42, 38, 34 (−4).
Q69. Find the next number in the series: 43, 47, 53, 59, 61, ?
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Answer: C. 67
These are consecutive prime numbers. Next = 67.
Q70. Find the next number: 9, 19, 29, 39, 49, ?
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Answer: C. 59
Each term increases by 10. 49 + 10 = 59.
Q71. Find the next number: 2, 4, 8, 16, 32, ?
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Answer: B. 64
Each term is multiplied by 2. 32 × 2 = 64.
Q72. Find the next number: 3, 6, 11, 18, 27, ?
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Answer: B. 38
The terms are n² plus 2 for n = 1, 2, … so the next is 6² plus 2 = 38.
Q73. Find the next number: 8, 17, 26, 35, 44, ?
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Answer: C. 53
Each term increases by 9. 44 + 9 = 53.
Q74. Find the next number: 3, 6, 12, 24, 48, ?
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Answer: D. 96
Each term is multiplied by 2. 48 × 2 = 96.
Q75. Find the next number: 27, 38, 51, 66, 83, ?
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Answer: D. 102
The terms are n² plus 2 for n = 5, 6, … so the next is 10² plus 2 = 102.
Q76. Find the next number in the series: 6, 11, 19, 30, 44, ?
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Answer: A. 61
Differences are 5, 8, 11, 14, 17 (increasing by 3). So 44 + 17 = 61.
Q77. Find the missing number in the series: 3, 56, 5, 51, ?, 46
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Answer: D. 7
Two alternating series: 3, 5, 7 (+2) and 56, 51, 46 (−5).
Q78. Find the next number in the series: 15, 21, 27, 33, 39, ?
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Answer: A. 45
Each term increases by 6: 39 + 6 = 45.
Q79. Find the missing number in the series: 10, 21, ?, 83, 165, 331
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Answer: C. 41
Pattern: ×2 + 1, ×2 − 1 alternately.
Q80. Find the next number in the series: 1, 4, 11, 22, 37, ?
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Answer: A. 56
Differences are 3, 7, 11, 15, 19 (increasing by 4). So 37 + 19 = 56.
Q81. Find the missing number in the series: 5, 32, 7, 28, 9, ?
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Answer: C. 24
Two alternating series: 5, 7, 9 (+2) and 32, 28, 24 (−4).
Q82. Find the missing number in the series: 8, 17, 33, 67, ?, 267
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Answer: C. 133
Pattern: ×2 + 1, ×2 − 1 alternately.
Q83. Find the next number in the series: 15, 20, 28, 39, 53, ?
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Answer: A. 70
Differences are 5, 8, 11, 14, 17 (increasing by 3). So 53 + 17 = 70.
Q84. Find the missing number in the series: 18, 47, 22, ?, 26, 33
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Answer: D. 40
Two alternating series: 18, 22, 26 (+4) and 47, 40, 33 (−7).
Q85. Find the next number in the series: 50, 65, 82, 101, 122, ?
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Answer: B. 145
Terms are n² + 1 for n = 7…12: 12² + 1 = 145.
Q86. Find the missing number in the series: 10, 21, 41, 83, ?, 331
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Answer: C. 165
Pattern: ×2 + 1, ×2 − 1 alternately.
Q87. Find the next number in the series: 28, 37, 46, 55, 64, ?
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Answer: C. 73
Each term increases by 9: 64 + 9 = 73.
Q88. Find the missing number in the series: 3, 7, 13, 27, 53, ?
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Answer: C. 107
Pattern: ×2 + 1, ×2 − 1 alternately.
Q89. Find the next number in the series: 9, 14, 23, 36, 53, ?
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Answer: A. 74
Differences are 5, 9, 13, 17, 21 (increasing by 4). So 53 + 21 = 74.
Q90. Find the missing number in the series: 19, 54, 21, ?, 23, 44
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Answer: D. 49
Two alternating series: 19, 21, 23 (+2) and 54, 49, 44 (−5).
Q91. Find the next number in the series: 19, 26, 33, 40, 47, ?
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Answer: D. 54
Each term increases by 7: 47 + 7 = 54.
Q92. Find the missing number in the series: 2, 5, 9, ?, 37, 75
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Answer: D. 19
Pattern: ×2 + 1, ×2 − 1 alternately.
Q93. Find the missing number in the series: 7, 15, 29, 59, ?, 235
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Answer: C. 117
Pattern: ×2 + 1, ×2 − 1 alternately.
Q94. Find the next number in the series: 61, 67, 71, 73, 79, ?
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Answer: B. 83
These are consecutive prime numbers. Next = 83.
Q95. Find the next number in the series: 15, 29, 43, 57, 71, ?
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Answer: D. 85
Each term increases by 14: 71 + 14 = 85.
Q96. Find the wrong number in the series: 13, 23, 35, 43, 53, 63, 73
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Answer: C. 35
Rule: add 10. The term should be 33, not 35.
Q97. Find the wrong number in the series: 14, 21, 30, 38, 46, 54, 62
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Answer: B. 21
Rule: add 8. The term should be 22, not 21.
Q98. Find the missing number in the series: 2, 37, 6, 33, 10, ?
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Answer: B. 29
Two alternating series: 2, 6, 10 (+4) and 37, 33, 29 (−4).
Q99. Find the next number in the series: 71, 73, 79, 83, 89, ?
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Answer: B. 97
These are consecutive prime numbers. Next = 97.
Q100. Find the wrong number in the series: 64, 81, 100, 121, 144, 168, 196
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Answer: D. 168
Rule: squares of 8 to 14. The term should be 169, not 168.
Q101. Find the wrong number in the series: 2, 5, 8, 16, 32, 64, 128
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Answer: B. 5
Rule: multiply by 2. The term should be 4, not 5.
Q102. Find the next number in the series: 12, 16, 23, 33, 46, ?
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Answer: B. 62
Differences are 4, 7, 10, 13, 16 (increasing by 3). So 46 + 16 = 62.
Q103. Find the missing number in the series: 5, 11, 21, 43, 85, ?
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Answer: C. 171
Pattern: ×2 + 1, ×2 − 1 alternately.
Q104. Find the next number in the series: 37, 41, 43, 47, 53, ?
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Answer: C. 59
These are consecutive prime numbers. Next = 59.
Q105. Find the next number in the series: 2, 3, 5, 7, 11, ?
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Answer: A. 13
These are consecutive prime numbers. Next = 13.
Q106. Find the wrong number in the series: 9, 16, 25, 36, 51, 64, 81
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Answer: D. 51
Rule: squares of 3 to 9. The term should be 49, not 51.
Q107. Find the wrong number in the series: 3, 6, 12, 24, 48, 95, 192
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Answer: A. 95
Rule: multiply by 2. The term should be 96, not 95.
Q108. Find the wrong number in the series: 17, 23, 29, 35, 41, 45, 53
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Answer: C. 45
Rule: add 6. The term should be 47, not 45.
Q109. Find the wrong number in the series: 16, 31, 40, 52, 64, 76, 88
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Answer: C. 31
Rule: add 12. The term should be 28, not 31.
Q110. Find the missing number in the series: 17, 33, 20, 28, ?, 23
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Answer: C. 23
Two alternating series: 17, 20, 23 (+3) and 33, 28, 23 (−5).
Q111. Find the next number in the series: 8, 9, 17, 26, 43, ?
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Answer: A. 69
Each term is the sum of the previous two. Next = 69.
Q112. Find the next number in the series: 9, 2, 11, 13, 24, ?
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Answer: A. 37
Each term is the sum of the previous two. Next = 37.
Q113. Find the wrong number in the series: 4, 8, 14, 32, 64, 128, 256
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Answer: C. 14
Rule: multiply by 2. The term should be 16, not 14.
Q114. Find the wrong number in the series: 9, 16, 26, 36, 49, 64, 81
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Answer: C. 26
Rule: squares of 3 to 9. The term should be 25, not 26.
Q115. Find the missing number in the series: 6, 13, ?, 51, 101, 203
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Answer: D. 25
Pattern: ×2 + 1, ×2 − 1 alternately.