On the Apple.SE about page, this answer is shown as accepted in the example question:
But that answer ("in my business we reatinoalize...") has only one vote in reality, making it the third-most voted answer:
This is very much intentional. The example question and answers are not meant to be accurate - they're meant to demonstrate the workings of the system. If you look at it before the system adds the checkmark, both answers are at a score of three.
In order to demonstrate the actions of upvoting and accepting an answer (and how that causes an answer to change positions), the second answer is upvoted and accepted which causes it to rise above the first. This happens when you scroll down the page far enough.
The questions (and answers) which appear on that page are randomly selected and automatically change after some unknown interval of time. Obviously one of the criteria is a question that has at least two answers, and it just selects two random answers out of that question for the demonstration.
You'll also notice that the answer in your screenshot has a score of 4 and a checkmark, while it's listed as having a score of 9 down in the section that talks about editing.