There is a better than even chance that Brian is yellow. There is almost no chance that John took the apple. It is highly unlikely that Mary discarded the milk. It is highly unlikely that if 'John took the apple' or 'Mary discarded the milk' or both then Julius is a rhino. Chances are slight that if either 'Brian is yellow' or 'Mary discarded the milk' but not both then Bernhard is yellow. It is probable that if 'Brian is yellow and John took the apple' then Lily is white.
Chances are slight that 'Brian is yellow' or 'Mary discarded the milk' or both.
There is a better than even chance that 'Brian is yellow' or 'Mary discarded the milk' or both.
Chances are slight that 'Brian is yellow' or 'Mary discarded the milk' 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
  0.6::factA.
  0.02::factB.
  0.05::factC.
  %hop1
  0.05::factX:-or(factB,factC).
  0.1::factY:-xor(factA,factC).
  0.7::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Brian is yellow' or 'Mary discarded the milk' or both.