If you're not already all quizzed out this is a fun way to spend some time. Some of you will have already done this, or a variation of it, so please don't spoil the fun 'n shenanigans for others.
i) I have done this before. It is possible to get the right answer (without cheating). You may need a few bits of paper to work on.
ii) Copied from the website: We were tempted to include the phrase "show your work" with the rules for entry but then we figured that any dork who would Google a puzzle like this in order to win would have to live with self-loathing and guilt for the rest of their life and that would far outweigh the value of the prize package.
iii) There is no prize, it's just for funsies.