It is likely that Jeff dropped the apple. It is certain that Winona is a wolf. It is improbable that Mary went to the hallway. There is little chance that if 'Mary went to the hallway and Jeff dropped the apple' then Brian is white. It is highly unlikely that if 'Winona is a wolf and Jeff dropped the apple' then Julius is a frog. It is highly likely that if either 'Winona is a wolf' or 'Mary went to the hallway' but not both then Bernhard is green.
It is probable that 'Julius is a frog and Brian is white'.
It is impossible that 'Julius is a frog and Brian is white'.
It is probable that 'Julius is a frog and Brian is white'.

  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
  0.7::factA.
  1.0::factB.
  0.1::factC.
  %hop1
  0.1::factX:-and(factC,factA).
  0.05::factY:-and(factB,factA).
  0.9::factZ:-xor(factB,factC).

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

  query(conclusion).
  
'Julius is a frog and Brian is white'.