In decipher jumbled up description type of questions, a round-about description is given in the form of certain small relationships and direct relationship between the persons concerned is to be deciphered.
Pointing to a photograph, a woman says, "This man`s son`s sister is my mother-in-law." How is the woman`s husband related to the man in the photograph ?
Man's son's sister -- Man's daughter.
So, the man's daughter is the mother of the woman's husband.
Thus, the woman's husband is the grandson of the man in the photograph.