The contest isn't limited to paid
I know that. Why do you think you need to tell me that?
And it doesn't matter what's in the top 100. Some random Joe could be downloading one of Samsung's apps to control his tv and that could be the 50B
SHERLOCK.
Of course that could happen, I just pointed out that your "bet" is useless, statistically. The chance of a popular app winning is larger than an app that is being downloaded once or twice altogether, that shouldn't need a Sherlock to understand (I hope).
(Unless you assume that Apple is manipulating the "winning" App - but then you surely would have said so. I won't read any implications into your post