It is impossible that Brian is white. We believe that John went to the bedroom. There is little chance that Julius is gray. There is a better than even chance that if 'John went to the bedroom' or 'Brian is white' or both then Greg is a rhino. There is little chance that if 'Julius is gray and Brian is white' then Bill moved to the office. It is almost certain that if 'Brian is white' or 'John went to the bedroom' or both then Lily is a swan.
Chances are about even that 'Julius is gray' or 'Greg is a rhino' or both.
Chances are about even that 'Julius is gray' or 'Greg is a rhino' or both.
It is almost certain that 'Julius is gray' or 'Greg is a rhino' or both.

  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
  0.0::factA.
  0.75::factB.
  0.1::factC.
  %hop1
  0.6::factX:-or(factB,factA).
  0.1::factY:-and(factC,factA).
  0.95::factZ:-or(factA,factB).

  %hop2
  conclusion:-or(factC,factX).

  query(conclusion).
  
'Julius is gray' or 'Greg is a rhino' or both.