A checklist for certainty
Many exam options include "Cannot be determined". It is right only when the clues fit more than one answer and no option states exactly what is known. In this lesson you run a five-point checklist before you choose, so a sure answer and a guess never look alike.
Guess first
Rina is the sister of Sohan's grandfather. How is Rina related to Sohan?
Show answer
Correct answer: A
The clue does not say which grandfather, so the side is open. But the relation is fixed: Rina is the sister of one of Sohan's grandfathers. "Grandfather's sister" says exactly that, so it is certain. In Hindi: दादा या नाना की बहन.
Option B: "Paternal" picks the father's side; no clue gives it.
Option C: An aunt is a parent's sister, one rung lower. Rina is a grandfather's sister.
Option D: Only the side is missing, and the first option does not need it.
Hint: What exactly is missing? Does any option avoid needing it?
Something was missing (the side), and still one option was certain. "Cannot be determined" is not the answer to "something is missing"; it is the answer to "the clues fit two different relations, and no option covers both".
A checklist before every answer
A pilot runs the same checklist before every flight, even a routine one.
Who to whom direction
start from the person after "related to"
Every link stated?
no link from habit
Side and gender given by a word?
father, sister, wife, son ...
Who could it be identity
can two descriptions be one person?
Decide one reading or several
name it, or choose what covers every reading
| What the clues leave open | Is there an option that states only what is known? | Choose |
|---|---|---|
| the side (which grandfather) | yes: "grandfather's sister" | that option |
| a gender (son or daughter) | yes: "child", "sibling", "cousin" | that option |
| who the person is (father or uncle) | yes: "father or paternal uncle" | that option |
| who the person is (father or uncle) | no | Cannot be determined |
See it: "the son of my grandmother"
Kiran says: "Arun is the son of my grandmother." Run the checklist.
Checklist for Arun and Kiran:
- Who to whom: Arun's relation to Kiran.
- Links: Kiran's grandmother, and her son Arun. Both are stated.
- Side: which grandmother? Not given.
- Who could it be: on the father's side, her son is Kiran's father or Kiran's father's brother; on the mother's side, her son is Kiran's mother's brother.
- Decide: three readings, three different answers.
flowchart TD G["Kiran's grandmother"] --> P["Kiran's father: Arun?"] G --> U["Kiran's father's brother: Arun?"] M["The other grandmother"] --> V["Kiran's mother's brother: Arun?"]
Three readings fit the words. Unless an option names all three, the answer is "Cannot be determined".
Try it on paper. Write one sentence about your own family that fits two different people. Then add the one word that fixes it.
Find the rule
Kiran said: "Arun is the son of my grandmother." How is Arun related to Kiran?
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Correct answer: D
The grandmother may be on the father's side or the mother's side, and her son may be Kiran's own parent. So Arun may be Kiran's father, paternal uncle or maternal uncle. No option covers all three.
Option A: That is one reading only: the father's mother, and her son is Kiran's father.
Option B: That is one reading only: the father's mother, and her other son.
Option C: That is one reading only: the mother's mother.
Hint: List every family the sentence fits. Do they all give the same answer?
P is Q's brother. R is P's mother, and S is R's father. Which statement is certain?
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Correct answer: A
P is Q's brother, so they share their mother R. S is R's father. So S is the father of Q's mother: Q's maternal grandfather, whatever Q's gender.
Option B: "Grandson" makes Q a man; Q's gender is not given.
Option C: P's link to S runs through his mother R: he is S's daughter's son.
Option D: R is S's daughter, not his daughter-in-law.
Hint: For each statement, check the side and every gender it needs.
Name the rule
Check, then decide.
- Who to whom: start from the person after "related to".
- Every link must be stated.
- Side and gender: use only what a word gives; otherwise use the plain word.
- Who could it be: ask whether two descriptions can be one person, or one description two people.
- Decide: if every reading gives one relation, that is the answer. If readings differ, choose the option that names them all, or else "Cannot be determined".
Exam options often include a plain word that is true in every reading: "grandfather's sister", "cousin", "uncle", "child". A missing detail makes the specific words unsafe, not the plain one. "Cannot be determined" is right only when no option is true in every reading.
Worked, half-done, solo
Question
Pointing to a man, Neha said: "He is the only son of my grandfather." How is the man related to Neha?
Solution
- Who to whom
The man's relation to Neha.
- Links
Neha's grandfather, and his only son. Both are stated.
- Side
Which grandfather? Not given.
- Who could it be
If it is her father's father, his only son is her father. If it is her mother's father, his only son is her mother's brother, her मामा.
- Decide
Two readings, two answers: father or maternal uncle.
Answer: Cannot be determined, unless an option says "father or maternal uncle".
Watch out: "Only" fixes the person once the side is known. Here the side is the missing piece.
Now finish one that is half done.
Mohit is the brother of Sunil's father's sister. Run the checklist: from Sunil, up to his father, across to the father's sister, then across to her brother Mohit. Who could Mohit be? The brother of the father's sister is Sunil's father himself, or another brother of his father. So Mohit is Sunil's ...
Show answer
Correct answer: A
Both readings are possible, and this option names exactly both: Mohit is Sunil's father or his paternal uncle.
Option B: That is one reading only. Mohit may be Sunil's father himself.
Option C: That is one reading only. Mohit may be another brother.
Option D: An option states exactly what is known, so "Cannot be determined" is not needed.
Hint: Does any option cover every reading?
And one on your own.
A is B's sister. C is B's father, and D is C's mother. Which statement is NOT certain?
Show answer
Correct answer: C
A and B share their father C, and D is C's mother. Statements about A are fixed: A is a woman (a sister). But B's gender is never given, so B may be D's granddaughter.
Option A: A's father is C, and D is C's mother: D is A's paternal grandmother.
Option B: A is a sister, a woman, and C is her father: A is C's daughter.
Option D: A and B share their parents, so C is A's father too.
Hint: Find the one statement that needs a gender no clue gives.
The traps
- "Cannot be determined" as an escape: choose it only when readings differ and no option covers them all.
- A specific word when the plain one is exact: "paternal" when the side is open.
- One reading taken as the answer: "the son of my grandmother" taken as "my father".
- A gender from a name, or from the wrong side of a code: only a word for that person gives it.
- "Only" ignored: "the only son" can turn two descriptions into one person.
P said: "Q's mother is my father's sister." Ajay said: "P's gender is not given, so Q's relation to P cannot be determined." What went wrong?
Show answer
Correct answer: A
Q's mother is the sister of P's father, so Q is the child of P's paternal aunt: P's cousin, फुफेरा भाई या बहन. P's gender does not change that.
Option B: Ajay's answer does not come from turning the sentence around; he gave up.
Option C: Ajay did not answer "sibling"; he gave up.
Option D: "Cousin (father's sister's child)" is certain in every reading.
Hint: Which missing detail would actually change the relation?
Mixed check
In a family, Arvind and Bela are husband and wife. Their son Chetan is married to Divya, and Esha is the daughter of Chetan and Divya. Who is Esha's paternal grandmother?
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Correct answer: A
Esha's father is Chetan, and Chetan's mother is Bela. So Bela is Esha's father's mother: her paternal grandmother, दादी.
Option B: Arvind is on the right rung and side, but he is the grandfather.
Option C: Divya is Esha's mother, one rung up.
Option D: Chetan is Esha's father, one rung up.
Hint: Lesson 11: walk from Esha through her father.
In a code, A + B means "A is the mother of B", A − B means "A is the brother of B", A × B means "A is the husband of B" and A ÷ B means "A is the daughter of B". From P × Q + R − S, which statement is certain?
Show answer
Correct answer: A
Q + R: Q is R's mother. R − S: R is S's brother, so Q is S's mother too.
Option B: S stands only on the right of a symbol, so S's gender is not given.
Option C: − makes R a brother: R is Q's son.
Option D: × makes P the husband, not the wife.
Hint: Lesson 9: decode each pair from the left.
Quick reference
Certainty checklist
- Who to whom
- start from the person after "related to" the reverse is a different answer
- Links
- each one stated no link from habit
- Side and gender
- given by a word? if not, use the plain word: grandfather's sister, cousin, uncle
- Who could it be
- can two descriptions be one person? the son of my grandmother: father or uncle
- Decide
- one reading: name it; several: the option naming all, or "Cannot be determined" never "Cannot be determined" when an exact option exists
Why it works: an answer is certain when every reading of the clues gives it. Checking the readings, not your first picture, separates a sure answer from a guess.
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