I married a widow (let’s call her wilma) who has a grown-up daughter (call her dolly). My father (frank), who visited us often, fell in love with my stepdaughter and married her. Hence my father became my son-in-law and my step-daughter became my mother. Some months later my wife gave birth to a son (sammy) who became the brother-in-law of my father. as well as my uncle. The wife of my father, that is, my step-daughter, also had a son (steven)
1. father (X,Y) ^ father (Y,Z) ? grandfather (X,Z)
2. father (X,Y) ^ married (Y,Z) ? father-in-law (X,Z)
3. father (X,Y) ^ mother (Y,Z) ? grandfather (X,Z)
4. father (X,Y) ^ father (X,Z) ? brother (Y,Z)
5. brother (X,Y) ^ grandfather (Z,Y) ? grandfather (Z,X)
6. married (I,W)
7. married (F,D)
8. father (I,S1)
9. father (I,D)
10.father (F,S2)
11.father (F,I)
12.mother (D,S2)
13.grandfather(I,S2)
USING 3:
9 ^ 12 ? grandfather (I, S2) (RESULT 1)
USING 4:
10 ^ 11 ? brother (S2,I) (RESULT 2)
USING 5: brother (X,Y) ^ grandfather (Z,Y) ? grandfather (Z,X)
Result2 ^ Result1
brother (I , S2) ^ grandfather (I, S2) ? grandfather (I, I)
THEREFORE, I AM MY OWN GRANDFATHER