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(2): solution to B by pleasance)

Ahhh! This exploits the fact that the question never asked us to determine whether in fact the false coin is lighter or heavier, we can gain more information about which one it is, in greater number of coins.

Excellent!

Posted by Charlie on 2003-05-19 04:30:47