UPSC Prelims 2020·CSAT·Logical Reasoning·Blood Relations

A family of two generations consisting of six members P, Q, R, S, T and U has three males and three females. There are two married couples and two unmarried siblings. U is P's daughter and Q is R's mother-in-law. T is an unmarried male and S is a male. Which one of the following is correct?

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  1. AR is U's husband
  2. BR is S's wifeCorrect
  3. CS is unmarried
  4. DNone of the above

Explanation

Let's break down the information to construct the family tree: 1. **Members:** P, Q, R, S, T, U (6 members) 2. **Generations:** Two generations 3. **Gender distribution:** 3 males, 3 females 4. **Marital status:** Two married couples, two unmarried siblings Now, let's use the specific clues: * **U is P's daughter:** This means U is female. P is in the first generation, U in the second. P (Gen 1) | U (Female, Gen 2) * **Q is R's mother-in-law:** This means Q is female. Q has a child who is married to R. So, Q is in the first generation, and her child and R are in the second. Q (Female, Gen 1) | Child (Gen 2) -- R (Gen 2) * **T is an unmarried male:** T is male and unmarried. He must be in the second generation as an unmarried sibling. * **S is a male:** S is male. Let's consolidate the known genders: U = Female Q = Female T = Male S = Male We need one more female and one more male to reach 3 males and 3 females. The remaining members are P and R. Let's assume P and Q are the married couple in the first generation. P -- Q (Female) Since Q is R's mother-in-law, Q's child is married to R. P and Q have children in the second generation. U is P's daughter. Consider the gender of P: If P is female, then P(-) -- Q(-), which is not possible for a married couple. Therefore, P must be male. So, P (Male) -- Q (Female) is the first married couple. Now we have P (Male), Q (Female), U (Female), T (Male), S (Male). The remaining member is R. To balance the genders (3 males, 3 females), R must be female. So, R = Female. The family structure is taking shape: Generation 1: P (Male) -- Q (Female) (Couple 1) Generation 2: Their children U, T, S (and R, who is married into the family) From "Q is R's mother-in-law," Q's child is married to R (Female). The children of P and Q are U (Female), T (Male), and S (Male). * U (Female) cannot be married to R (Female). * T is an unmarried male. So T cannot be married to R. * Therefore, S (Male) must be the child of P and Q who is married to R (Female). So, S (Male) -- R (Female) is the second married couple. Now, let's verify all conditions with the derived family tree: Generation 1: P (Male) -- Q (Female) Generation 2: S (Male) -- R (Female) U (Female, unmarried sibling) T (Male, unmarried sibling) * **Members:** P, Q, R, S, T, U - All accounted for. * **Genders:** P(M), Q(F), S(M), R(F), U(F), T(M). (3 Males, 3 Females) - Correct. * **Generations:** P,Q in Gen 1; S,R,U,T in Gen 2 - Correct. * **Married couples:** (P, Q) and (S, R) - Two couples. Correct. * **Unmarried siblings:** U and T - Two unmarried siblings. Correct. * **U is P's daughter:** U is the daughter of P and Q. Correct. * **Q is R's mother-in-law:** Q is S's mother, and S is married to R. So Q is R's mother-in-law. Correct. * **T is an unmarried male:** Correct. * **S is a male:** Correct. The family tree is consistent with all given information. Now, let's evaluate the options: A) R is U's husband R is female, U is female. R is S's wife. This is incorrect. B) R is S's wife R is female, S is male, and they are married in our derived tree. This is correct. C) S is unmarried S is married to R. This is incorrect. D) None of the above Since option B is correct, this is incorrect. The final answer is B. The final answer is B
Logical Reasoning: A family of two generations consisting of six members P, Q, R, S, T and U has three males and three females. There are t

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