Originally posted by findingnewidea:
here is the proof. to make it easy, i don't consider
whether you pass your birthday. everyone is older when 1 jan 2005
hits.
1. First of all, pick the number of times a week that you would
like to
have chocolate
(more than once but less than 10)
[b] define x:= chocolate number. we will see this number as the
first digit.
2. Multiply this number by 2 (just to be bold)
2x
3. Add 5
2x+5
4. Multiply it by 50 -- I'll wait while you get the
calculator
(2x+5)*50 = 100x + 250
5. If you have already had your birthday this year add 1755 .... If
you haven't, add 1754.
just assume everyone passes the birthday, so +1755
100x+250+1755 = 100x+2005
now you see something...
6. Now subtract the four digit year that you were born.
100x+2005-birthyear = 100x + age,
as x is single digit, after multiplying with 100, you will see it
as the third digit. Age is even simpler, 2005 - birthyear
definitely gives you your age.
Easy.
You should have a three digit number.
The first digit of this was your original number (i.e., how many
times you want to have chocolate each week).
The next two numbers are YOUR AGE! (Oh YES, it is!!!!!)
proof given as above
Apparently it only works in Year 2005.
to make it work for other years, you got to change the +1755 to
+1756 (2006), +1757 (2007) and so on
Now, geniuses help come up with the proof why this works.
[/b]
Well done... best explanation there is... 
