Explanation
1) A, B, C, D, E and F are six members in a family in which there are two married couples.
2) D is brother of F.
3) Both D and F are lighter than B.
4) C a lady, is neither heaviest nor lightest in the family.
5) E is lighter than C.
6) The grandfather is the family is the heaviest.
In terms of weight, F < B, D < B, B < E, E < C. So, we have : D < F < B < E < C or F < D < B < E < C. C is not the
heaviest. So, A is the heaviest. Thus, the sequence becomes : F < D < B < E < C < A or D < F < B < E < C < A.
D is the brother of F.
B is the mother of D and F.
A, being the heaviest, is the grandfather.
Now, C is a lady and so one couple is AC.
B is a female and so on cannot pair up with C. So, the other couples is BE.
C is the wife of A and A is the grandfather of D. So, C is the grandmother of D
