http://mathpuzzlewiki.com/api.php?action=feedcontributions&feedformat=atom&user=Waldhell 2026-04-05T18:04:35Z User contributions MediaWiki 1.44.0 http://mathpuzzlewiki.com/index.php?title=The_thief_and_the_murderer&diff=1386 2019-01-23T14:42:13Z

<p>Waldhell: Waldhell moved page The thief and the murderer to Who does which?: Wrong title</p> <hr /> <div>#REDIRECT [[Who does which?]]</div>

Waldhell http://mathpuzzlewiki.com/index.php?title=Who_does_which%3F&diff=1385 2019-01-23T14:42:12Z

<p>Waldhell: Waldhell moved page The thief and the murderer to Who does which?: Wrong title</p> <hr /> <div>There are three people, Demarcus, Eli and Dominic. One is a farmer, one is a salesman and one is a debt collector, but you don't know who does which. You ask them about their job and get the following answers:<br /> * Demarcus: Eli is not a debt collector and Dominic is a salesman.<br /> * Eli: Demarcus is a farmer and Dominic is not a debt collector.<br /> * Dominic: Eli is not a salesman and Demarcus is a debt collector.<br /> A friend of yours who had listened to the conversation tells you: &quot;Actually, only one of them told the truth&quot;. Which is the job of each of them?<br /> <br /> {{hint|Think about boolean algebra and proceed with the method of proof by contradiction.}}<br /> {{answer|Dominic is a farmer, Eli is a debt collector and Dominic is a salesman.}}<br /> {{solution|Let's assume that Demarcus told the truth. Then Dominic is a salesman and Demarcus is a debt collector. But then Dominic also told the truth. That's a contradiction. Let's assume that Dominic told the truth. Then Demarcus is a debt collector and Dominic is a salesman. But then Demarcus also told the truth. Another contradiction. So, the one who told the truth is Eli. Then, Demarcus is a farmer, Eli is a debt collector and Dominic is a salesman.}}</div>

Waldhell http://mathpuzzlewiki.com/index.php?title=Who_does_which%3F&diff=1384 2019-01-13T14:34:13Z

<p>Waldhell: Created page with &quot;There are three people, Demarcus, Eli and Dominic. One is a farmer, one is a salesman and one is a debt collector, but you don&#039;t know who does which. You ask them about their...&quot;</p> <hr /> <div>There are three people, Demarcus, Eli and Dominic. One is a farmer, one is a salesman and one is a debt collector, but you don't know who does which. You ask them about their job and get the following answers:<br /> * Demarcus: Eli is not a debt collector and Dominic is a salesman.<br /> * Eli: Demarcus is a farmer and Dominic is not a debt collector.<br /> * Dominic: Eli is not a salesman and Demarcus is a debt collector.<br /> A friend of yours who had listened to the conversation tells you: &quot;Actually, only one of them told the truth&quot;. Which is the job of each of them?<br /> <br /> {{hint|Think about boolean algebra and proceed with the method of proof by contradiction.}}<br /> {{answer|Dominic is a farmer, Eli is a debt collector and Dominic is a salesman.}}<br /> {{solution|Let's assume that Demarcus told the truth. Then Dominic is a salesman and Demarcus is a debt collector. But then Dominic also told the truth. That's a contradiction. Let's assume that Dominic told the truth. Then Demarcus is a debt collector and Dominic is a salesman. But then Demarcus also told the truth. Another contradiction. So, the one who told the truth is Eli. Then, Demarcus is a farmer, Eli is a debt collector and Dominic is a salesman.}}</div>

Waldhell