It is highly unlikely that Lily is white. We believe that Sumit is thirsty. We doubt that Sandra left the football. It is highly unlikely that if 'Lily is white and Sandra left the football' then Julius is a frog. It is probable that if 'Lily is white' or 'Sandra left the football' or both then Brian is a rhino. It is highly likely that if 'Sandra left the football and Sumit is thirsty' then Mary went to the garden.
There is a better than even chance that 'Sandra left the football and Brian is a rhino'.
It is improbable that 'Sandra left the football and Brian is a rhino'.
There is a better than even chance that 'Sandra left the football and Brian is a rhino'.

  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
  0.05::factA.
  0.75::factB.
  0.2::factC.
  %hop1
  0.05::factX:-and(factA,factC).
  0.7::factY:-or(factA,factC).
  0.9::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Sandra left the football and Brian is a rhino'.