GATE ECE 2017 Set 2 | GA | Question: 7

Question

Each of $P, Q, R, S, W, X, Y$and $Z$ has been married at most once . $X$ and $Y$ are married and have two children $P$ and $Q$. $Z$ is the grandfather of the daughter $S$ of $P$. Further , $Z$ and $W$ are married and are parents of $R$. Which one of the following must necessarily be FALSE?

• A. $X$ is the mother-in-law of $R$
• B. $P$ and $R$ are not married to each other
• C. $P$ is a son of $X$ and $Y$
• D. $Q$ cannot be married to $R$

Comments

This question requires analytical thinking.

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This is a bad aptitude question. You can't deduce anything from the provided facts and have to make huge leaps in logic to get the answer.

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yes , how can anyone marry there brother or sister ? This question is wrong. Option B and D both are correct.

Answer 1

Let $\to$ represent the child relation.

• $\{X,Y\} \to P, Q$
• $P \to S$
• $\{Z,W\}\to R$
• Further $P's$ spouse is the child of $Z$ so that $S$ become the grand daughter of $Z.$

1.  $X$ is the mother-in-law of $R$ -- possible if $R$ is married to either $P$ or $Q.$
2. $P$ and $R$ are not married to each other -- $P$ has only $R$ to marry as $Q$ is a sibling and $S$ daughter, but $P$ can also be married to anyone not mentioned in the question. So, this is possible.
3. $P$ is a son of $X$ and $Y$ -- possible as $P$ can either be a son or daughter of $X$ and $Y.$
4. $Q$ cannot be married to $R$ -- FALSE as $Q$ can be married to $R.$ 

Correct Option: D

Comments

@Teja25, I don't seen such possibilities in analytical thinking. Eventhough that possibility exist in the real life. 

I may be wrong.

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I think option B is true, because A\Q  Z is grandfather of S and also parent of R.
AND the most important part of the question, Each of P,Q.R,S,W,X,Y and Z has been married at most once.
hence Option D is true but we want necessarily false.

 

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But for Z to be grandfather of S, P should be married to R right?

Answer 2

https://gateoverflow.in/139221/gate-ece-2017