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)

A: N=(2^(x+1))-1
B: N=2x-1

A and B are two completely different problems.
You must find the most efficient way of weighing.

Posted by geoffrey on 2003-10-09 14:53:17