Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site dciem.UUCP Path: utzoo!dciem!ntt From: ntt@dciem.UUCP (Mark Brader) Newsgroups: net.math Subject: Re: New Probability problems: answers Message-ID: <414@dciem.UUCP> Date: Wed, 28-Sep-83 17:24:15 EDT Article-I.D.: dciem.414 Posted: Wed Sep 28 17:24:15 1983 Date-Received: Thu, 29-Sep-83 04:09:58 EDT References: <516@houxz.UUCP>, <1210@stolaf.UUCP> Organization: NTT Systems Inc., Toronto, Canada Lines: 11 The answer previously posted to the "lost club?" problem is wrong; stolaf!koch (Paul Koch) has the right result, but there is a much easier way to obtain it. 5 cards were drawn and are known to be clubs. The remaining 47 cards including the lost card contain 8 clubs. We have no information about which of the 47 cards was lost. Therefore the probability that the lost card is a club is 8/47 (or .1702 for those who prefer approximations). The fact that the card was lost before the 5 cards were drawn is irrelevant, because we did not see it and therefore have no information about it. Mark Brader, NTT Systems Inc., Toronto