We believe that John went to the office. There is little chance that Sandra left the football. It is likely that Lily is a lion. It is highly unlikely that if 'Lily is a lion and Sandra left the football' then Gertrude is a mouse. It is unlikely that if either 'Sandra left the football' or 'Lily is a lion' but not both then Brian is green. We believe that if 'Lily is a lion' or 'Sandra left the football' or both then Julius is a rhino.
There is a better than even chance that 'Julius is a rhino and Brian is green'.
Chances are slight that 'Julius is a rhino and Brian is green'.
There is a better than even chance that 'Julius is a rhino and Brian 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
  0.75::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.05::factX:-and(factC,factB).
  0.2::factY:-xor(factB,factC).
  0.75::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Julius is a rhino and Brian is green'.