What's the answer to this hard IQ test problem?

Question

http://images.google.com/imgres?imgurl=http://www.math.ups.edu/~anierman/umich/smartest/engin-web/brain-1lg.gif&imgrefurl=http://www.math.ups.edu/~anierman/umich/smartest/&h=170&w=200&sz=6&hl=en&start=1&sig2=VG1U9BoBOdN04NRR0R7eJA&um=1&tbnid=HYy_fRS3vjgJfM:&tbnh=88&tbnw=104&ei=CoPkR6aNKZLIhgKq-PXdBQ&prev=/images%3Fq%3DAndrew%2BNierman%26um%3D1%26hl%3Den%26sa%3DN

Answer 1

Um, just took the test.  My IQ is 144.

Answer 2

(1) BOX

(2) 10

(3) 50%

Answer 3

To add to the above answer.. i think that number 3 is 66.6%

Answer 4

1) Have no idea.  Actually I didn't have the patience to try.  If I were to do it, I would look for the most common letter and substitute it for the most commonly used letter: E.

2) 8 pieces.  That's all I got.

3) 50%.