Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.albasani.net!.POSTED!not-for-mail From: Frederick Williams Newsgroups: sci.logic,rec.puzzles,sci.math.num-analysis,comp.programming Subject: Re: the hourglass problem Date: Mon, 02 Jan 2012 17:18:44 +0000 Organization: albasani.net Lines: 13 Message-ID: <4F01E6F4.912FE850@btinternet.com> References: <7f48dfe5-ca54-49ca-8cb9-5ae686e96f92@c42g2000prb.googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news.albasani.net q9nB++ttyv1/rKuTaQmIhqVZ3LqO2436KOeKA+wV5Q7HwO1HP1B1d3f6ONqRpVbCgfCwWQqieaJ1f0Ebd/uDvw== NNTP-Posting-Date: Mon, 2 Jan 2012 17:18:43 +0000 (UTC) Injection-Info: news.albasani.net; logging-data="wAAtzW4pMk4F8HfK9WUJrlV5QarHPeyYbE7Bh4nqOYYL6R7IcjtBsn0INoN0mrPhMAFejR195B6VBrDp90m5jPusyGi2kp68KiTORwn2figWFebS6AZFzpD2cNWsuOr1"; mail-complaints-to="abuse@albasani.net" X-Mailer: Mozilla 4.8 [en] (Windows NT 5.0; U) X-Accept-Language: en Cancel-Lock: sha1:sowQ4NZc1W+pfSwe/+qvopYDBEk= Xref: x330-a1.tempe.blueboxinc.net comp.programming:1186 RichD wrote: > > You're given a 7 minute, and a 4 minute, sand > hourglass. Measure a 9 minute interval, in the first > 9 minutes. (no 'setup' period) Take the 7 minute and 4 minute sand hourglasses to an hourglass shop. Trade them in for a 9 minute hourglass. -- When a true genius appears in the world, you may know him by this sign, that the dunces are all in confederacy against him. Jonathan Swift: Thoughts on Various Subjects, Moral and Diverting