Pointing to a woman,Nirmal said,"She is the daughter of my wife's grandfather's only child". How is the woman related to Nirmal?

$A$ 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. Which of the following are the two married couples?

$A + B$ means $A$ is the father of $B$; $A - B$ means $A$ is the wife of $B$; $A \times B$ means $A$ is the brother of $B$; $A \div B$ means $A$ is the daughter of $B$.
If $P - R \times Q$,which of the following is true?

If $P \times Q$ means $P$ is wife of $Q$,$P + Q$ means $P$ is father of $Q$,and $P \div Q$ means $P$ is sister of $Q$,then in $G \times H + R \div D$,how is $G$ related to $D$?

$A$ party consists of a grandmother,a father,a mother,four sons and their wives,and one son and two daughters for each of the sons. How many females are there in all?

$A$ 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?