Pointing to a photograph,a person tells his friend,"She is the granddaughter of the elder brother of my father." How is the girl in the photograph related to the person?

$A$ 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 $X$?

Pointing to a photograph,Nikita said,'She is the only granddaughter of my grandmother's daughter'. How is the girl in the photograph related to Nikita?

There is a family of six persons $A, B, C, D, E,$ and $F$. They are a lawyer,doctor,teacher,salesman,engineer,and accountant. There are two married couples in the family. $D$,the salesman,is married to the lady teacher. The doctor is married to the lawyer. $F$,the accountant,is the son of $B$ and brother of $E$. $C$,the lawyer,is the daughter-in-law of $A$. $E$ is the unmarried engineer. $A$ is the grandmother of $F$. How is $D$ related to $F$?

$A$ 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 $P$. Who is the father of $Q$?

Arun said,'This girl is the wife of the grandson of my mother'. Who is Arun to the girl?