Let's see... I recall 40 piece coming with 6, so I already know 0.1 is off. That's 40:6, so 0.15.
That said, you can get pretty good nugget coverage with 6 nuggets to a sauce. I recently asked for one of each sauce when getting a 40 and that was 7 sauces, and they didn't charge more cause I clearly was ordering with the curious whimsy of someone who had never had a 40 pack before. After all, this wasn't a planned visit, fates simply lead us there that evening.
With a ratio of 0.175, there was plenty leftover, although popular sauces Honey Mustard and Ranch did almost run out. I imagine even with a 0.1 ratio, there should be enough sauce to satisfy all but the most gluttonous sauce abusers, assuming you only get sauces people are willing to eat.