They've changed it up a few times over the years.
This is how they've done it in the past a couple times. But, last year, I distinctly remember that they kept Ginger around to the bitter end. I remember screaming my head off,
"YEEEEEEESSSSSS!!!! THERE IS A GOD!!!!" while typing their names into the computer that she came in THIRD. I was so unprepared for it, because I thought for sure she'd be announced the winner. And I remember marveling that I could type & be yelling something different at the same time.
No, it's not 50/50. They changed that when Bristol Palin made it to the Finals. The producers didn't want their DANCE show hijacked for political reasons, or some other reason, so they introduced that the judges get one more final vote to make sure that the winners won because of
dancing. So that's why they get an extra vote on Tues. The math for voting became so convoluted that Tom had to point to some chart they created to show how the voting worked out. I never could figure it out, but I assumed the math would have been called out to be incorrect, if it is. So I *think* the judges get 60% for the scoring, if not more.
The judges USUALLY just score everyone equally the same, so their votes probably don't change anything. But, it definitely did for Bristol as they only gave her 8s while the other two contestants got 9s & 10s. The only other time that I can recall that they didn't vote the same for each couple was when Ginger screwed up and they had to mark her down. And there may be one other time where they didn't score them all the same.