There is almost no chance that Greg is a rhino. We doubt that Mary got the football. It is probably the case that Fred dropped the apple. It is impossible that if either 'Mary got the football' or 'Fred dropped the apple' but not both then Lily is yellow. There is little chance that if either 'Mary got the football' or 'Fred dropped the apple' but not both then John went to the hallway. We believe that if either 'Fred dropped the apple' or 'Mary got the football' but not both then Winona is a mouse.
It is highly unlikely that 'John went to the hallway and Fred dropped the apple'.
It is highly unlikely that 'John went to the hallway and Fred dropped the apple'.
It is highly likely that 'John went to the hallway and Fred dropped the apple'.

  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
  0.02::factA.
  0.2::factB.
  0.7::factC.
  %hop1
  0.0::factX:-xor(factB,factC).
  0.1::factY:-xor(factB,factC).
  0.75::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'John went to the hallway and Fred dropped the apple'.