JKSSB Sub-Inspector Reasoning: Series, Coding, Blood Relations & Direction MCQs

Reasoning · 2026-10-13 · 8 min read

In the JKSSB Sub-Inspector (Executive) paper, General Intelligence & Reasoning carries 40 of 200 marks, the joint-largest section. It is also very learnable: four topic types cover most questions. Here is a method for each.

Negative marking is −0.5, so avoid blind guesses. Solve what you can do in under 40 seconds first.

1. Number series

Check these in order: differences, second differences, multiply and add (×2+1), squares/cubes (n² + 1), factorial (1, 2, 6, 24, 120).

2. Coding–decoding

Write the alphabet positions (A=1 … Z=26) and find the shift. If MANGO becomes NBOHP, every letter moves +1, so apply +1 to the new word.

3. Blood relations

Break the sentence one step at a time. 'My mother's only son' is my brother (or me). Draw a small tree if it has more than three people.

4. Direction and distance

Sketch the path on paper. Opposite moves cancel: 5 km north then 5 km south returns you to the same line. Then use the Pythagoras rule for diagonal distances.

Where to practise

Use the 12 MCQs below, then continue on Practice by Topic for the Sub-Inspector and Class-IV reasoning sets (browsing is open; a free account starts tests). See also analogy MCQs and the Sub-Inspector syllabus.

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Practice questions

Q1. Find the next term: 3, 7, 15, 31, 63, ?

  1. 95
  2. 111
  3. 127
  4. 131
Show answer

127 — Each term is double the previous plus 1: 63 × 2 + 1 = 127.

Q2. Find the next term: 2, 5, 10, 17, 26, ?

  1. 35
  2. 36
  3. 37
  4. 38
Show answer

37 — The terms are n² + 1: 1²+1, 2²+1 … 6²+1 = 37.

Q3. Find the next term: 1, 2, 6, 24, 120, ?

  1. 240
  2. 600
  3. 720
  4. 840
Show answer

720 — The multipliers are 2, 3, 4, 5, then 6: 120 × 6 = 720.

Q4. Find the next term: 4, 9, 16, 25, 36, ?

  1. 42
  2. 45
  3. 49
  4. 64
Show answer

49 — These are squares: 7² = 49.

Q5. If MANGO is coded as NBOHP, APPLE is coded as:

  1. BQQMF
  2. BPPMF
  3. CQQMF
  4. BQQLE
Show answer

BQQMF — Each letter moves one step ahead: A→B, P→Q, P→Q, L→M, E→F.

Q6. If DOG is coded as GRJ, then CAT is coded as:

  1. FDW
  2. FDV
  3. EDW
  4. FEW
Show answer

FDW — Each letter moves three steps ahead: C→F, A→D, T→W.

Q7. Pointing to a man, a woman says, 'He is the son of my mother's only son.' How is the man related to her?

  1. Brother
  2. Nephew
  3. Son
  4. Cousin
Show answer

Nephew — Her mother's only son is her brother, so the man is her brother's son: nephew.

Q8. A is the brother of B. B is the sister of C. C is the father of D. How is A related to D?

  1. Uncle
  2. Father
  3. Brother
  4. Grandfather
Show answer

Uncle — A is C's brother, so A is D's paternal uncle.

Q9. A man walks 5 km north, then 3 km east, then 5 km south. How far is he from the start?

  1. 3 km
  2. 5 km
  3. 8 km
  4. 13 km
Show answer

3 km — The north and south moves cancel, leaving 3 km east.

Q10. Facing north, a person turns right and then turns right again. Which direction does the person now face?

  1. East
  2. South
  3. West
  4. North
Show answer

South — North → East → South.

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