It is almost certain that Bernhard is white. Chances are about even that Sumit is bored. There is a very good chance that Greg is a rhino. We doubt that if either 'Sumit is bored' or 'Bernhard is white' but not both then Brian is a lion. It is probable that if 'Greg is a rhino' or 'Sumit is bored' or both then John went to the hallway. It is impossible that if 'Greg is a rhino' or 'Bernhard is white' or both then Sandra left the apple.
It is impossible that 'John went to the hallway' or 'Brian is a lion' or both.
It is probable that 'John went to the hallway' or 'Brian is a lion' or both.
It is impossible that 'John went to the hallway' or 'Brian is a lion' 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
  0.95::factA.
  0.5::factB.
  0.8::factC.
  %hop1
  0.2::factX:-xor(factB,factA).
  0.7::factY:-or(factC,factB).
  0.0::factZ:-or(factC,factA).

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

  query(conclusion).
  
'John went to the hallway' or 'Brian is a lion' or both.