Pointing to a lady,a man said,"The son of her only brother is the brother of my wife." How is the lady 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 is $Q$ related to $X$?

$A$ is the brother of $B$. $B$ is the brother of $C$. $D$ is the father of $A$. Based on these three statements,which of the following statements cannot be definitely true?

$A$ family consists of six members $P, Q, R, S, T,$ and $U.$ There are two married couples. $Q$ is a doctor and the father of $T.$ $U$ is the grandfather of $R$ and is a contractor. $S$ is the grandmother of $T$ and is a housewife. There is one doctor,one contractor,one nurse,one housewife,and two students in the family. Who is the sister of $T?$

Pointing to a person,a man said to a woman,"His mother is the only daughter of your father." How was the woman related to the person?

When Amy saw Manish,she recalled,"He is the son of the father of my daughter." Who is Manish?