Chances are slight that Brian is a rhino. It is almost certain that Mary dropped the apple. Chances are slight that Julius is a frog. It is likely that if 'Julius is a frog' or 'Brian is a rhino' or both then Gertrude is a sheep. It is unlikely that if either 'Brian is a rhino' or 'Julius is a frog' but not both then John went to the office. It is unlikely that if 'Brian is a rhino' or 'Julius is a frog' or both then Greg is green.
It is impossible that 'John went to the office and Greg is green'.
It is impossible that 'John went to the office and Greg is green'.
It is highly likely that 'John went to the office and Greg is green'.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.1::factA.
  0.95::factB.
  0.1::factC.
  %hop1
  0.7::factX:-or(factC,factA).
  0.2::factY:-xor(factA,factC).
  0.2::factZ:-or(factA,factC).

  %hop2
  conclusion:-and(factY,factZ).

  query(conclusion).
  
'John went to the office and Greg is green'.