to jeff/all i misinterpreted the question, which lead to the wrong formula (which was statistically wrong anyway), which of course lead to the wrong answer :( sorry guys. dennis profeta VANCE,JEFF (HP-Cupertino,ex1) <[log in to unmask]> wrote in message news:F4B1826B1A21D211AEC5006008207AF404377D7D@dogbert.csillc.com... > > chances of six heads in a row in twenty tosses > > 6!/14! = 8.258936e-9 > > my wife thinks. why so low? it is because you have to do it > > in sequence of six. > > 00111111000000000000 is okay > > 01010101010100000000 is not > > But, 01111111111111111 is also OK. So is > 11111111111111111 and > 11111101111110111 and > 01111110111111000 etc. etc... > > I interpret the question to mean you just need to have 6 heads in a row. > You can have more but not less. > > Jeff >