In "5 dice"
Andy had five regular dice. Now he has a total of N regular dice. He claims that the odds of rolling exactly M sixes is exactly half as likely as rolling (M-1) sixes. (M < N).
For what values of N is this true?
State the pattern if there is one.
Express M as a function of N.
(In reply to Solution
Very nice, hoodat.
It took me a while to figure out that your 2.5 factor was the fivefold increase in combinations times 1/2 (the desired ratio of probabilities). Once I figured this out, all was well.
I checked out your first case, N = 6 and M = 2, and it had the desired 1/2 relative probability