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JKSSB Junior Engineer (Mechanical) · Reasoning · 44 practice questions with answers and explanations: 22 Easy, 21 Medium, 1 Hard.

Sample questions

Sample Easy question 1

Find the next number: 100, 90, 80, 70, ?

  1. 55
  2. 50
  3. 65
  4. 60
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Answer: D. The series decreases by 10 each time, so next is 60.

Sample Easy question 2

Find the next number: 2, 5, 10, 17, ?

  1. 24
  2. 28
  3. 26
  4. 25
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Answer: C. The pattern is n²+1: 1²+1=2, 2²+1=5, 3²+1=10, 4²+1=17, 5²+1=26.

Sample Easy question 3

Find the next number: 2, 6, 12, 20, 30, ?

  1. 42
  2. 44
  3. 40
  4. 41
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Answer: A. Each term is n(n+1): 1×2, 2×3, 3×4, 4×5, 5×6, 6×7=42.

Sample Medium question 4

In this interleaved series, find the next term: 3, 100, 7, 90, 11, 80, ?

  1. 75
  2. 70
  3. 15
  4. 16
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Answer: C. Two interleaved series: odd positions increase by 4 (3,7,11,15...) and even positions decrease by 10 (100,90,80...); the next term (7th, odd position) is 11 + 4 = 15.

Sample Medium question 5

Find the next letter-number term: C3, F9, I27, L81, ?

  1. P243
  2. N243
  3. O162
  4. O243
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Answer: D. Letters skip two each time (C,F,I,L,O) and the number is multiplied by 3 each time (3,9,27,81,243), giving O243.

Sample Medium question 6

Find the missing number: 6, 11, 21, 41, ?, 161

  1. 76
  2. 81
  3. 84
  4. 79
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Answer: B. Each term follows (previous × 2) - 1: 41 × 2 - 1 = 81 (check: 81 × 2 - 1 = 161).

Sample Hard question 7

Find the next number: 2, 5, 14, 41, ?

  1. 124
  2. 122
  3. 128
  4. 120
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Answer: B. Each term follows (previous × 3) - 1: 41 × 3 - 1 = 122.

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