P % Q → P is the mother of Q
Q + R → Q is the father of R
R - T → R is the brother of T
Hence, → Q is the father of T
T x K → T is the daughter of K
Hence, → Q is the husband of K.
Therefore, P is the mother-in-law of K.
Brother of person's wife → brother-in-law of the person. Hence, the son of lady's brother is brother-in-law of the person.
Therefore, the brother of the lady is the father-in-law of the person. Hence, the lady is the sister of the person's father-in-law.