Pointing to a gentleman,Deepak said,"His only brother is the father of my daughter's father." How is the gentleman related to Deepak?

$E$ is the son of $A$. $D$ is the son of $B$. $E$ is married to $C$. $C$ is $B$'s daughter. How is $D$ related to $E$?

$A$ woman walking with a boy meets another woman and on being asked about her relationship with the boy,she says,"My maternal uncle and his maternal uncle's maternal uncle are brothers." How is the boy related to the woman?

$X$ introduces $Y$ saying,"He is the husband of the granddaughter of the father of my father." How is $Y$ related to $X$?

$A + B$ means $A$ is the son 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 mother of $B$; and $A = B$ means $A$ is the sister of $B$. What does $P + R - Q$ mean?

Pointing to the lady on the platform,Manju said,"She is the sister of the father of my mother's son." Who is the lady to Manju?