Given a balance scale that is sure to break after X weighings, find an equation for the largest number of coins N, from which you can determine a fake coin that has the wrong weight if

A: You know whether the fake is lighter or heavier

B: You do not know whether the fake is lighter or heavier

(Assume only one of the N coins is fake)

(In reply to re(3): solution to B by Charlie)

Yes, Charlie, and interestingly, it seems to me that in each of the cases it's only ONE COIN which is never weighed, that is, for n coins we distinguish between 2n-1 cases.

Posted by pleasance on 2003-05-19 06:49:49