There is little chance that Greg is a rhino. It is almost certain that John went to the hallway. It is impossible that Mary got the apple. It is probably not the case that if 'Greg is a rhino' or 'Mary got the apple' or both then Lily is green. There is little chance that if either 'Mary got the apple' or 'Greg is a rhino' but not both then Sandra took the milk. It is impossible that if either 'Mary got the apple' or 'Greg is a rhino' but not both then Bernhard is a frog.
There is almost no chance that 'Lily is green' or 'Bernhard is a frog' or both.
There is almost no chance that 'Lily is green' or 'Bernhard is a frog' or both.
Chances are about even that 'Lily is green' or 'Bernhard is a frog' 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
  0.1::factA.
  0.95::factB.
  0.0::factC.
  %hop1
  0.25::factX:-or(factA,factC).
  0.1::factY:-xor(factC,factA).
  0.0::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Lily is green' or 'Bernhard is a frog' or both.