You are correct, there was a transcription error on the second formula, it should be:
(0.72 * 0.5 * 0.53) + //lose first, win next two
(0.28 * 0.5) + //win first two
(0.28 * 0.5 * 0.53) //win first, lose second, win third
Basically, I modified the wrong value on the third line. Anyways that does indeed give me 0.405. I'll fix the original post for posterity.
Also, the odds of winning all three aren't part of the calculation, I think you maybe actually omitted the third line? If you represent it visually with a markov chain (
Markov chain - Wikipedia ) you have two terminal nodes, >= 2 and <2. Indeed from the second line Tennessee could move on to win all three, but that result is excluded from the chain as we have already reached the >= 2 terminal.
Anyways, that's probably enough math for one thread.