Among 100 coins exactly 4 are fake. All genuine coins weigh the same; all fake coins, too. A fake coin is lighter than a genuine coin.
How would we find at least one genuine coin using two weighings on a balance scale?
Source: 2010 Euler math Olympiad in Russia- authored by A.Shapovalov
(In reply to re: question for Kenny
by Kenny M)
Along the same lines of an original RF vs RF, what if the next weighing had those four: RRFF against, say RRRF. The heavy side is not all R; you might choose the F.
Posted by Charlie
on 2013-10-19 01:38:08