It is probable that Brian is a frog. There is almost no chance that Julius is yellow. It is impossible that Jeff dropped the apple. There is little chance that if 'Julius is yellow and Jeff dropped the apple' then John went to the hallway. It is impossible that if either 'Brian is a frog' or 'Julius is yellow' but not both then Bill moved to the office. It is highly unlikely that if 'Brian is a frog and Julius is yellow' then Bernhard is yellow.
It is impossible that 'John went to the hallway and Julius is yellow'.
It is impossible that 'John went to the hallway and Julius is yellow'.
It is probably the case that 'John went to the hallway and Julius is yellow'.

  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.
  0.02::factB.
  0.0::factC.
  %hop1
  0.1::factX:-and(factB,factC).
  0.0::factY:-xor(factA,factB).
  0.05::factZ:-and(factA,factB).

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

  query(conclusion).
  
'John went to the hallway and Julius is yellow'.