There are six persons A, B, C, D , E and F. C is the sister of F. B is the brother of E's husband. D is the father of A and grandfather of F. There are two fathers, three brothers and a mother in the group.
Who is the mother ?
D is father of A and grandfather of F. So, A is father of F. Thus, D and A are the two fathers. C is the sister of F. So, C is the daughter of A. Since there is only one mother, it is evident that E is the wife of A and hence the mother of C and C and F. So, B is brother of A. There are three brothers. So, F is the brother of C.
Clearly, E is the mother.