There is a better than even chance that Jeff went to the bedroom. It is probably the case that Jessica is a cat. It is likely that Brian is a frog. Chances are slight that if either 'Jessica is a cat' or 'Jeff went to the bedroom' but not both then Greg is a frog. It is highly likely that if 'Brian is a frog' or 'Jeff went to the bedroom' or both then Sandra left the football. We believe that if 'Jeff went to the bedroom' or 'Brian is a frog' or both then Julius is yellow.
It is impossible that 'Julius is yellow and Brian is a frog'.
Chances are about even that 'Julius is yellow and Brian is a frog'.
It is impossible that 'Julius is yellow and Brian is a frog'.

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

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

  query(conclusion).
  
'Julius is yellow and Brian is a frog'.