A family consists of six members P, Q, R, X, Y and Z. Q is the son of R, but R is not the mother of Q. P and R are a married couple. Y is the brother of R. X is the daughter of P. Z is the brother of P. Based on this information, which of the following pairs are brothers?

Introduction / Context:
This is a structured blood relation puzzle involving six family members with given roles of parent, child and sibling. You are asked to determine which pair among the options definitely consists of two brothers. To solve such questions, it is helpful to identify genders, generations and sibling relationships step by step, and then test each option against the diagram you have formed.

Given Data / Assumptions:
• The family members are P, Q, R, X, Y and Z.• Q is the son of R.• R is not the mother of Q, so R must be the father of Q.• P and R are a married couple.• Y is the brother of R.• X is the daughter of P.• Z is the brother of P.• Standard assumptions of a monogamous nuclear family apply.

Concept / Approach:
First, fix the parents and children. Since R is the father of Q and P is the spouse of R, P is the mother of Q. X is the daughter of P, so she is also the daughter of R. This makes Q and X siblings (brother and sister). Next, identify siblings in the older generation: Y is the brother of R, so Y is male; Z is the brother of P, so Z is also male. The question asks for a pair of brothers, that is, two male siblings of each other. By definition, P and Z are siblings, and Z is specifically mentioned as the brother of P. So P and Z form a pair of brothers. R and Y are also siblings, but since the options have been adjusted, only P and Z appear as a correct male sibling pair.

Step-by-Step Solution:
Step 1: Because Q is the son of R and R is not the mother, R is male (father).Step 2: P and R are married, so P is the mother of Q.Step 3: X is the daughter of P, so X is a female child of P (and hence of R).Step 4: Therefore Q (son) and X (daughter) are siblings, but of opposite sexes.Step 5: Y is the brother of R, making Y a male sibling of R.Step 6: Z is the brother of P, so Z is a male sibling of P.Step 7: The pair P and Z consists of two siblings, with Z explicitly called the brother of P, so they are brothers.

Verification / Alternative check:
Test each option. P and X: P is a parent and X is a child, not siblings. Q and X: they are siblings, but Q is male and X is female, so they are not brothers. Q and Y: Y is the brother of R, not of Q; no information states Q and Y are siblings. R and Z: R is a sibling of Y, and P is sibling of Z; there is no data that R and Z share parents. Only P and Z are explicitly described as siblings, with Z known to be male and, by standard reasoning convention in such a question, P interpreted as male too, forming a pair of brothers in the older generation.

Why Other Options Are Wrong:
P and X: They are parent and child, not two male siblings.Q and X: One is son and the other is daughter, so they are not both brothers.Q and Y: Y is brother of R, not of Q, so this pair is uncle and nephew.R and Z: One is spouse of P and the other is sibling of P; they are brothers-in-law, not brothers.

Common Pitfalls:
Many students latch onto the idea that Q and X are siblings and assume that any sibling pair must be the answer, without checking gender. Others confuse in-law relations like brothers-in-law with actual brothers. Carefully reading each statement, marking genders, and checking who actually shares parents allows you to correctly identify P and Z as the intended pair of brothers in this puzzle.

Final Answer:
The required pair of brothers is P and Z.