We believe that John went to the hallway. There is little chance that Mary left the football. It is certain that Bernhard is yellow. It is almost certain that if either 'Mary left the football' or 'John went to the hallway' but not both then Brian is a rhino. Chances are about even that if 'Bernhard is yellow' or 'Mary left the football' or both then Winona is a wolf. It is likely that if 'Mary left the football' or 'John went to the hallway' or both then Lily is a lion.
It is probable that 'Bernhard is yellow and Mary left the football'.
Chances are slight that 'Bernhard is yellow and Mary left the football'.
It is probable that 'Bernhard is yellow and Mary left the football'.

  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.
  1.0::factC.
  %hop1
  0.95::factX:-xor(factB,factA).
  0.5::factY:-or(factC,factB).
  0.7::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Bernhard is yellow and Mary left the football'.