We believe that Jessica is a sheep. It is improbable that Brian is white. There is little chance that Mary left the apple. Chances are about even that if either 'Mary left the apple' or 'Brian is white' but not both then John went to the bedroom. It is probable that if either 'Brian is white' or 'Mary left the apple' but not both then Emily is a wolf. It is improbable that if 'Mary left the apple' or 'Jessica is a sheep' or both then Julius is a rhino.
We believe that 'Brian is white and Jessica is a sheep'.
It is improbable that 'Brian is white and Jessica is a sheep'.
We believe that 'Brian is white and Jessica is a sheep'.

  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
  0.75::factA.
  0.1::factB.
  0.1::factC.
  %hop1
  0.5::factX:-xor(factC,factB).
  0.7::factY:-xor(factB,factC).
  0.1::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Brian is white and Jessica is a sheep'.