THis question is absolutely impossible to answer. Not a chance that you could come up with an answer which is correct in any real , useful way. Some 10 handicappers are better putters than scratch markers, and vice versa. Handicap does not reflect putting ability, and in the case of 5 handicap v scratch, their putting ability is very close anyway, so every 5 handicapper could be better than the scratch handicappers. I would say that the chances are approx 45%, but like i say, that answer is purely intuition, no formula could do it.