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HCL Tech Hiring Coding Decoding — practice questions

Explore 123 free Coding Decoding questions in HCL Tech Hiring Reasoning. Open each question or exercise to read its content, reference answers and available explanation.

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Coding Decoding questions and exercises with answers

Showing questions 1–30 of 123.

Find the next number: 2, 6, 12, 20, 30, ?Read the answer and worked solution →Find the next number: 1, 4, 9, 16, 25, ?Read the answer and worked solution →Find the next: 3, 7, 15, 31, 63, ?Read the answer and worked solution →Find the next: 1, 1, 2, 3, 5, 8, ?Read the answer and worked solution →Find the missing: 5, 11, 23, 47, ?, 191Read the answer and worked solution →Find the next: 8, 27, 64, 125, ?Read the answer and worked solution →Find the next: 100, 50, 25, 12.5, ?Read the answer and worked solution →Find the next: A, C, E, G, ?Read the answer and worked solution →Find the missing: B, D, F, H, ?, LRead the answer and worked solution →Find the next: AZ, BY, CX, DW, ?Read the answer and worked solution →Find the next: ACE, BDF, CEG, ?Read the answer and worked solution →Doctor : Hospital :: Teacher : ?Read the answer and worked solution →Pen : Write :: Knife : ?Read the answer and worked solution →Bird : Fly :: Fish : ?Read the answer and worked solution →Hunger : Food :: Thirst : ?Read the answer and worked solution →Light : Blind :: Sound : ?Read the answer and worked solution →Botany : Plants :: Cardiology : ?Read the answer and worked solution →3 : 27 :: 4 : ?Read the answer and worked solution →5 : 24 :: 8 : ?Read the answer and worked solution →7 : 56 :: 9 : ?Read the answer and worked solution →Statements: All cats are mammals. All mammals are animals. Conclusion: All cats are animals.Read the answer and worked solution →Statements: Some dogs are brown. All brown things are animals. Conclusion: Some dogs are animals.Read the answer and worked solution →Statements: No teachers are lazy. Some teachers are intelligent. Conclusion: Some intelligent are not lazy.Read the answer and worked solution →Pointing to a photograph, Rohan said: 'She is my mother's only daughter's daughter.' How is the girl related to Rohan?Read the answer and worked solution →A is B's father. C is A's son. D is B's only sister. How is C related to D?Read the answer and worked solution →In a family, P is M's son. N is P's sister. Q is M's mother. How is Q related to N?Read the answer and worked solution →X is Y's brother. Z is Y's mother. W is Z's father. How is W related to X?Read the answer and worked solution →If CAT = 3-1-20, then DOG = ?Read the answer and worked solution →In a code language, ROSE is coded as SPTF (each letter shifted by +1). How is LILY coded?Read the answer and worked solution →In a coded language, if HAPPY = IBQQZ, then how is SAD coded?Read the answer and worked solution →

Worked practice questions

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

  1. 40
  2. 36
  3. 42
  4. 44
Show answer and solution

Correct answer: C. 42

**Differences:** 4, 6, 8, 10 (increasing by 2). Next difference = 12. So 30 + 12 = 42. Equivalent: n(n+1) for n=1,2,3,... giving 2, 6, 12, 20, 30, 42.

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Find the next number: 1, 4, 9, 16, 25, ?

  1. 49
  2. 36
  3. 32
  4. 30
Show answer and solution

Correct answer: B. 36

Series of perfect squares: 1², 2², 3², 4², 5². Next = 6² = 36.

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Find the next: 3, 7, 15, 31, 63, ?

  1. 125
  2. 99
  3. 127
  4. 95
Show answer and solution

Correct answer: C. 127

Each term is 2 × previous + 1: 3 → 7 (2×3+1), 7 → 15 (2×7+1), 15 → 31, 31 → 63, 63 → 127. Or 2ⁿ⁺¹ - 1.

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More Reasoning topics

Distance and DirectionNumber SeriesBlood RelationsAnalogyAnalogiesVenn DiagramsNumber Series, Coding and Decoding and Odd Man OutDirection Sense