Blood Relations • Topic 4 of 4

Coded Relations

Symbols stand for relations: e.g., 'A + B' means A is the father of B, 'A - B' means A is the wife of B. Substitute each symbol with its meaning, build the tree, then read off the asked relation.

Decode, then draw

You are given a key such as: A + B = A is the father of B; A × B = A is the brother of B. To solve "P + Q × R":

  1. P + Q ⇒ P is the father of Q.
  2. Q × R ⇒ Q is the brother of R.
  3. So P is the father of R's brother ⇒ P is the father of R.
Always write the key first. List each symbol's meaning on your sheet, substitute symbol by symbol, then build the family tree. Never try to decode and conclude in your head.

Reading direction

Apply the operators left to right, exactly as written, and let the tree grow. Two generations of "+ / parent" stacked (A + B + C) makes A the grandparent of C.

✅ Solved examples

1. If A + B means A is father of B, and B × C means B is brother of C, then in 'P + Q × R', how is P related to R?
P is father of Q; Q is brother of R → P is father of R.
2. If A - B means A is wife of B, then in 'X - Y', how is Y related to X?
X is the wife of Y → Y is the husband.
3. If A × B means A is brother of B, and A + B means A is mother of B, then in 'M + N × O', how is M related to O?
M is mother of N; N is brother of O → M is mother of O.
4. If P + Q means P is parent of Q, then in 'P + Q + R', how is P related to R?
P is parent of Q; Q is parent of R → P is grandparent of R.

✏️ Practice — try these, take hints as needed

1. A + B = A father of B; A × B = A sister of B. In 'X + Y × Z', how is X related to Z?
X father of Y; Y sister of Z.
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Father
2. A - B = A wife of B. In 'M - N', how is N related to M?
M is N's wife.
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Husband
3. A + B = A mother of B; A - B = A husband of B. In 'P - Q + R', how is P related to R?
P husband of Q; Q mother of R.
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Father
4. A + B = A parent of B. In 'A + B + C', how is A related to C?
Two generations down.
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Grandparent
5. A × B = A brother of B. In 'X × Y', Y could be X's?
Sibling.
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Brother or sister

📝 Topic test — 8 questions

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