I'm posting one puzzle, riddle, math, or statistical problem a day. Try to answer each one and post your answers in the comments section. I'll post the answer the next day. Even if you have the same answer as someone else, feel free to put up your answer, too!
Tuesday, July 31, 2007
What's Wrong With That?
The following is what seems to be a mathematical proof that ten equals 9.999999.... What's wrong with it?
a = 9.999999... 10a = 99.999999... 10a - a = 90 9a = 90 a = 10