It is improbable that Julius is a frog. It is probably not the case that Mary is in the bathroom. It is highly likely that John went to the kitchen. Chances are slight that if 'Julius is a frog and Mary is in the bathroom' then Daniel got the milk. Chances are about even that if 'Julius is a frog' or 'Mary is in the bathroom' or both then Bernhard is a rhino. We doubt that if 'Julius is a frog and John went to the kitchen' then Greg is yellow.
It is probably not the case that 'John went to the kitchen and Mary is in the bathroom'.
It is probably not the case that 'John went to the kitchen and Mary is in the bathroom'.
There is a very good chance that 'John went to the kitchen and Mary is in the bathroom'.

  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.
  0.25::factB.
  0.9::factC.
  %hop1
  0.1::factX:-and(factA,factB).
  0.5::factY:-or(factA,factB).
  0.2::factZ:-and(factA,factC).

  %hop2
  conclusion:-and(factC,factB).

  query(conclusion).
  
'John went to the kitchen and Mary is in the bathroom'.