[JoeAltmaier]

I don't get it - if there are 2 participants, you need N-1 == 2-1 == 1 game to determine the winner. The ah-ha answer still works.

[drbaskin]

The a-ha answer still works, but the orignal answer given has you sum 2^(d-k) from k =0 to d, so in this example would be 2^1 + 2^0, suggesting that you would need 3 games to determine the winner.