3*4 means 3 is the mother of 4.
3 #4 means 3 is the father of 4.
3 @ 4 means 3 is the brother of 4.
3 & 4 means 3 is the daughter of 4.
3+4 means 3 is the son of 4.
According to L@M&N#O+P*Q#R, how is M related to R?

Let's decode the expression L@M&N#O+P*Q#R from left to right:
1. $L@M⟹L$ is the brother of $M$.
2. $M\&N⟹M$ is the daughter of $N$. (So $N$ is the parent of $L$ and $M$).
3. $N\#O⟹N$ is the father of $O$. (Thus, $N$ is a male and the father of $L,M,O$).
4. $O+P⟹O$ is the son of $P$. Since $N$ is the father, $P$ must be the mother ($N$ and $P$ are a married couple).
5. $P\ast Q⟹P$ is the mother of $Q$. (So $Q$ is also a child of $N$ and $P$).
6. $Q\#R⟹Q$ is the father of $R$.

From the above relations, $M$ is a female child of $N$ and $P$, and $Q$ is a male child of $N$ and $P$. This means $M$ is the sister of $Q$. Since $Q$ is the father of $R$, $M$ is the paternal aunt of $R$.