Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site decwrl.UUCP Path: utzoo!linus!decvax!decwrl!dec-rhea!dec-alien!schoeller From: schoeller@alien.DEC (Todd Schoeller) Newsgroups: net.puzzle Subject: A puzzle with two answers?!? Message-ID: <4@decwrl.UUCP> Date: Mon, 12-Nov-84 09:07:41 EST Article-I.D.: decwrl.4 Posted: Mon Nov 12 09:07:41 1984 Date-Received: Tue, 13-Nov-84 06:10:31 EST Sender: daemon@decwrl.UUCP Organization: DEC Engineering Network Lines: 68 -Newsgroups: net.puzzle -Path: decwrl!decvax!mcnc!duke!ucf-cs!hollis -Subject: Figure me this... -Posted: Wed Nov 7 09:49:36 1984 - -You are shipwrecked and wash ashore onto an island populated by -cannibals. There are two types of cannibals on this island: -short ones who always tell the truth and tall ones who always lie. - -As you crawl up the beach, one of the short ones, the chief, -approaches you and makes you an offer you can't refuse. - -The chief blindfolds you and places three men from his tribe -near you on the beach. From what they say to you, you must -tell the chief which are short and which are tall - and prove -your answer. If you manage to do this, you will be set free. -Otherwise, you are invited to dinner. - -As the first tribesman begins to speak, a wave breaks on the -nearby reef and drowns out his voice. Then you hear the -second say 'The first one said he is short and he is, and so -am I". The third one says 'The second one is lying, he is -tall and I am short'. - -You have all the information I had... and I lived to tell -about it. - - -Ken Hollis =============================================================================== Mr. Hollis, Your not becoming dinner for those tribesmen was by luck. This riddle has 2 answers. Therefore, you must have taken a wild guess about the type of tribes- men in front of you. The two answers are : 1) The first is short, 2) The first is tall, the second is short, and OR the second is tall, and the third is tall. the thirs is short. Proof: We are given that all the tall tribesmen will always lie. We are given that the short tribesmen will always tell the truth. We are also given that we did not hear what the first tribesman said. From the conversa- tion, we have this... Case 1: If the second person is short, then the first person must also be short since a short tribesman must always tell the truth. Therefore, the third person must be tall since he said that the second was lying (and in fact, the second was not). Therefore, in this situation, one of the answers is that the first person is short and must of said that he was short, the second person is short, and the third person is tall. Case 2: If the second person is tall, then the first person must also be tall since the second person said that the first person is short and the second person MUST lie. Therefore, the third person must be telling the truth since he said that the second person was lying (and the second was indeed lying). Therefore, in this situation, the other answer is that the first is tall, the second is tall, and the third is short. THEREFORE... The person had a 50-50 chance of being the main course for dinner. And in that case, luck, NOT LOGIC, is what saved that person from being eaten. Good puzzel. It's like saying what is 'X' if X**2 ('X' squared) equals 4. You have a 50-50 chance of getting it right with '2' or '-2'. If there is only one answer to this puzzel, please post it with the proof. Thank you. Todd Schoeller.