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Two counterfeit coins

✍ Scribed by Ratko Tošić

Publisher
Elsevier Science
Year
1983
Tongue
English
Weight
413 KB
Volume
46
Category
Article
ISSN
0012-365X

No coin nor oath required. For personal study only.

✦ Synopsis

We consider the problem of ascertaining the minimum number of weighings which sufike to determine the counterfeit (heavier) coins ia a set of n coins of the same appearance, given a balance scale and the information that there are exactly two heavier coins present. An optimal procedure is constructed for infinitely many n's, and for all other n's a lower bound and an upper bound for the maximum number of steps of an optimal procedure are determined which differ by just one unit. Some results of Cairns are improved, and his conjecture at the end of [33 is proved in a slightly modified form.

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