There is a very good chance that Brian is yellow. There is a very good chance that Bernhard is a frog. It is certain that Sandra dropped the milk. It is highly unlikely that if 'Bernhard is a frog and Brian is yellow' then Greg is yellow. There is almost no chance that if 'Brian is yellow' or 'Sandra dropped the milk' or both then Lily is a rhino. It is probable that if either 'Bernhard is a frog' or 'Brian is yellow' but not both then Mary went to the hallway.
There is a very good chance that 'Bernhard is a frog and Lily is a rhino'.
There is almost no chance that 'Bernhard is a frog and Lily is a rhino'.
There is a very good chance that 'Bernhard is a frog and Lily is a rhino'.

  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
  0.8::factA.
  0.8::factB.
  1.0::factC.
  %hop1
  0.05::factX:-and(factB,factA).
  0.02::factY:-or(factA,factC).
  0.7::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Bernhard is a frog and Lily is a rhino'.