It is almost certain that Daniel got the football. Chances are slight that Julius is white. It is likely that Sumit is thirsty. There is a very good chance that if either 'Julius is white' or 'Sumit is thirsty' but not both then Lily is green. It is likely that if 'Sumit is thirsty and Daniel got the football' then Greg is gray. It is likely that if 'Daniel got the football' or 'Julius is white' or both then John left the apple.
It is highly unlikely that 'Greg is gray and Julius is white'.
It is highly unlikely that 'Greg is gray and Julius is white'.
It is highly likely that 'Greg is gray and Julius is white'.

  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
  0.95::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.8::factX:-xor(factB,factC).
  0.7::factY:-and(factC,factA).
  0.7::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Greg is gray and Julius is white'.