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SSC CGL Reasoning · Blood Relations

Coded Relations

Symbols stand for relations ('A @ B means A is the mother of B'), and a chain like 'K # L @ M' is decoded into plain links and drawn as a family tree.

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Why this matters

Forty-four questions in the bank, twenty-six of them from the 2024 shifts and twenty-nine MODERATE. The code changes from question to question, so nothing can be memorised, but the method never changes: split the chain into links, translate each one, and fill the gaps the links leave.

Concept 1 of 2: Decoding a symbol chain link by link

A coded chain is a statement chain with the words replaced by symbols. Put the words back one link at a time, draw each link as you go, and the question becomes a Direct Relations question you already know how to solve.

Definition

1. Read the code table printed with this question. Each line reads 'left person is the ... of right person' unless it says otherwise. 2. Split the chain into links. In 'P @ Q # R & S' the links are P @ Q, Q # R and R & S; every middle person appears in two links. 3. Translate each link into words and draw it on the tree, in order. 4. Read the asked relation along the tree, one step per link, from the person asked about. 5. Fix the answer person's gender from any link where they stand on the left of a gendered word. 6. Fast route: you rarely need the whole chain. Decode only the links between the two people asked about, then check the gender.

Worked example

In a code, 'A @ B' means 'A is the mother of B', 'A # B' means 'A is the brother of B' and 'A & B' means 'A is the husband of B'. In 'K # L @ M & N', how is K related to M?
Practice this conceptself-check · 4 quick reps

The same idea in a real exam question:

SSC CGL · 2025 · Tier I, 14 Sep 2025, Shift 3 · Q18Easy

Example 1 · Blood Relations · Coded Relations

P + Q means P is the husband of Q, P −- Q means P is the sister of Q, P ×\times Q means P is the mother of Q. Then what does A ×\times B + C mean?

Reading a code from the wrong side

'A + B means A is the son of B' puts A one level below B. Reading it as 'B is the son of A' flips the whole tree, and the flipped answer is usually printed as an option.

Carrying a code over from another question

The same symbol means 'mother' in one shift and 'son' in the next. Decode only with the table printed beside the question you are solving.

Leaving the answer person's gender open

'Father's sister' and 'father's brother' differ only in gender. Look for any link where that person stands on the left of a gendered word; it may be the last link in the chain.
Drill 26 more on decoding a symbol chain link by link

Concept 2 of 2: Filling a gap: the other parent and a gender fixed by a later link

Codes often leave a hole: two links name two different parents of one child, or a person's gender only appears three links later. The answer sits in that hole, so the skill is to see what the links say together, not one at a time.

Definition

  • If one link names X as a child's mother and another names Y as a parent of a sibling of that child, Y is the father, and X and Y are a married couple.
  • 'X is the wife of Y' and 'Y is the father of C' make X the mother of C.
  • A gender may appear only in a later link where the person is on the left: 'S is the wife of A' makes S female even if S appeared earlier as someone's child.
  • A reversed code ('P @ Q means Q is the mother of P') gives the relation to the person on the right. Rewrite every link in plain words before drawing.
  • If the gender the answer needs never appears, and 'Cannot be determined' is printed, choose it.

Worked example

In a code, 'A ~ B' means 'A is the son of B', 'A ! B' means 'A is the mother of B' and 'A = B' means 'A is the sister of B'. In 'M ! N = O ~ P', how is P related to M?
Practice this conceptself-check · 4 quick reps

The same idea in a real exam question:

SSC CGL · 2025 · Tier I, 21 Sep 2025, Shift 3 · Q17Moderate

Example 2 · Blood Relations · Coded Relations

Directions: These questions are based on the following information: 'P@Q' means 'Q is the mother of P'. 'P$Q' means 'Q is the husband of P'. 'P#Q' means 'Q is the sister of P'. 'P&Q' means 'Q is the son of P'. If 'A & B @ C & D # E' then how is A related with E?

Making the other parent a second mother

When one parent of a child is named as the mother, any other parent named for the same child is the father, and the two are husband and wife. SSC builds many options on missing this.

Missing a reversed code

A line such as 'P @ Q means Q is the mother of P' gives the relation to the person on the right. Read every code line to the end; never assume the usual left-to-right direction.
Drill 16 more on filling a gap: the other parent and a gender fixed by a later link

Summary — formulas & gotchas at a glance

A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.

Watch out for (5)

Test yourself on Blood Relations

20 past SSC CGL questions from this chapter, timed at 12 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.

Take the Blood Relations chapter testDrill all 44 questions