It is probable that Greg is yellow. Chances are about even that Bernhard is green. It is improbable that John went to the hallway. There is little chance that if 'Bernhard is green and John went to the hallway' then Sumit is thirsty. It is improbable that if either 'Bernhard is green' or 'John went to the hallway' but not both then Antoine is hungry. There is a very good chance that if 'Bernhard is green and Greg is yellow' then Julius is a frog.
We doubt that 'Sumit is thirsty' or 'Greg is yellow' or both.
It is probably the case that 'Sumit is thirsty' or 'Greg is yellow' or both.
We doubt that 'Sumit is thirsty' or 'Greg is yellow' 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
  0.7::factA.
  0.5::factB.
  0.1::factC.
  %hop1
  0.1::factX:-and(factB,factC).
  0.1::factY:-xor(factB,factC).
  0.8::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Sumit is thirsty' or 'Greg is yellow' or both.