Pointing to a man,a woman said,"His mother is the only daughter of my mother." How is the woman related to the man?

$A$ 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 $P$.
How many children does $P$ have?

Pointing to a photograph,a man tells his friend,"She is the daughter of the only son of my father's wife." How is the girl in the photograph related to the man?

There are six persons $A, B, C, D, E$ and $F$. $C$ is the sister of $F$. $B$ is the brother of $E$'s husband. $D$ is the father of $A$ and grandfather of $F$. There are two fathers,three brothers,and a mother in the group. Who is the mother?

Pointing to a man on the stage,Rita said,"He is the brother of the daughter of the wife of my husband." How is the man on the stage related to Rita?

If Kamal says,"Ravi's mother is the only daughter of my mother," how is Kamal related to Ravi?