P's father is Q's son. M is the paternal Uncle of P and N is the brother of Q.…

In blood-relation puzzles, every stated link (father, son, brother, uncle) is either a parent-child link or a sibling link. Two people are in an uncle-nephew relationship exactly when one is the sibling of the other's parent. So the puzzle reduces to three steps: build the parent-child chain from the clues, identify the sibling pairs, then apply the rule 'sibling of a parent = uncle of that parent's child' to the two people the question asks about.

Applying this to the puzzle:

1. "P's father is Q's son" means Q is the parent of P's father.

2. "M is the paternal Uncle of P" means M is the brother of P's father, so M is also a child of Q (a sibling of P's father).

3. "N is the brother of Q" means N and Q are siblings.

4. Since M is a child of Q, and N is Q's sibling, N is the sibling of M's parent.

5. By the rule above, N is M's uncle.

Cross-check with a small family tree: Q and N sit in the same (older) generation as siblings; P's father and M sit one generation below as Q's children. N has no direct parent-child link to M but is the sibling of M's parent — that is precisely the uncle relationship, confirming Uncle.