An improved strategy for a counterfeit coin problem (Corresp.)

Mead, in a recent paper, considers the problem of minimizing the average number of weighings required using a balance to find one counterfeit light coin from among coins, of which are genuine coins of equal weight. The solution given here is in many cases strictly better than Mead\´s one--the reason being that Mead disregards the possible use of genuine coins in the weighing experiment.