{"id":1578,"date":"2018-10-25T16:00:43","date_gmt":"2018-10-25T23:00:43","guid":{"rendered":"http:\/\/areteem.org\/blog\/?p=1578"},"modified":"2018-10-24T14:11:18","modified_gmt":"2018-10-24T21:11:18","slug":"3-more-of-the-weirdest-math-problems-continued","status":"publish","type":"post","link":"https:\/\/areteem.org\/blog\/3-more-of-the-weirdest-math-problems-continued\/","title":{"rendered":"3 More of the Weirdest Math Problems\u2014Continued"},"content":{"rendered":"<p>It seems like a lot of folks loved the previous post, so we&#8217;re going at it again! Here are three more <a href=\"https:\/\/areteem.org\/ziml-math-competition\/the-onsite-ziml-math-competition\" target=\"_blank\" rel=\"noopener\">hard math problems<\/a> that don&#8217;t make much sense or are difficult to solve!<\/p>\n<h6>The missing dollar math problem<\/h6>\n<p>This particular problem is pretty popular, but for those who haven&#8217;t come across it, take a gander below:<\/p>\n<blockquote><p>&#8220;Three people check into a hotel room. The clerk says the bill is $30, so each guest pays $10. Later the clerk realizes the bill should only be $25. To rectify this, he gives the bellhop $5 to return to the guests. On the way to the room, the bellhop realizes that he cannot divide the money equally. As the guests didn&#8217;t know the total of the revised bill, the bellhop decides to just give each guest $1 and keep $2 as a tip for himself. Each guest got $1 back, so now each guest only paid $9, bringing the total paid to $27. The bellhop has $2. And $27 + $2 = $29 so, if the guests originally handed over $30, what happened to the remaining $1?&#8221;<\/p><\/blockquote>\n<p>The Missing Dollar Math Problem (or Riddle) stumps a lot of even the most seasoned mathematicians! One of the biggest reasons why this particular problem can be so confusing is in the\u00a0<strong>misdirection of totals<\/strong>. \u00a0There&#8217;s a focus on arbitrary factors of money that can be easily dismissed if you think about the location of each of the dollars.<\/p>\n<p><strong>The bellhop has 5 dollars, 2 of them he keeps and 3 of them go to the guests.<\/strong><\/p>\n<p><strong>The cash register has 25<\/strong>\u00a0<strong>dollars.\u00a0<\/strong><\/p>\n<p><strong>Our sum is 30$.<\/strong><\/p>\n<p>The misdirection is in the dollar amount that the guests &#8220;paid&#8221; when you factor in the 3 dollars they get back. Technically, they paid approximately\u00a0<span style=\"text-decoration: underline;\">8.33 dollars,<\/span> or 8 dollars and 33 cents per capita when you add their discount\u2014not 9 dollars. 8.33 x 3 = 25 dollars (okay, there&#8217;s one cent missing), and the bellhop has 5, 3 of which he gives back to the guests. They now have paid 9 dollars and 33 cents, a total of 28 dollars (rounded, again), and the bellhop pocketed the extra 2. There&#8217;s plenty more information that dissects this problem, so be sure to <a href=\"https:\/\/en.wikipedia.org\/wiki\/Missing_dollar_riddle\" target=\"_blank\" rel=\"noopener\">read up on it<\/a> if you&#8217;re still stumped. There are other variations of this, too!<\/p>\n<h6>dividing by zero will not work, ever<\/h6>\n<p>If you&#8217;ve ever successfully divided by zero, we would suddenly all be skeptical of that claim, or we&#8217;re headed towards a paradoxical black hole that will consume everything in a fraction of a second. Calculators will often spit out &#8220;UNDEFINED&#8221; or &#8220;CANNOT DIVIDE BY ZERO&#8221; depending on the model used. Quite literally, the math problem &#8220;X\/0&#8221; means &#8220;take zero out of this number,&#8221; which doesn&#8217;t mean anything. It&#8217;s such a weird concept in math that a division by zero once <a href=\"https:\/\/en.wikipedia.org\/wiki\/USS_Yorktown_(CG-48)\" target=\"_blank\" rel=\"noopener\">disabled the propulsion systems of the USS Yorktown<\/a>. Don&#8217;t mess with zero.<\/p>\n<h6>Whose Birthday is it Anyways?<\/h6>\n<p>Cheryl&#8217;s Birthday is a logic puzzle that apparently has stumped several minds across the world. Originally thought to be a math problem aimed at elementary school students, the problem actually originated from the\u00a02015 Singapore and Asian Schools <a href=\"https:\/\/areteem.org\/courses\/math-zoom-club\" target=\"_blank\" rel=\"noopener\">Math Olympiad<\/a> program, targeted towards older students. This is a mind-bender of a problem, so be forewarned:<\/p>\n<blockquote><p>Albert and Bernard just became\u00a0friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates:<\/p>\n<table class=\"wikitable\">\n<tbody>\n<tr>\n<th>May<\/th>\n<td><\/td>\n<td>15<\/td>\n<td>16<\/td>\n<td><\/td>\n<td><\/td>\n<td>19<\/td>\n<\/tr>\n<tr>\n<th>June<\/th>\n<td><\/td>\n<td><\/td>\n<td><\/td>\n<td>17<\/td>\n<td>18<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<th>July<\/th>\n<td>14<\/td>\n<td><\/td>\n<td>16<\/td>\n<td><\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<th>August<\/th>\n<td>14<\/td>\n<td>15<\/td>\n<td><\/td>\n<td>17<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.<\/p>\n<p>Albert: I don&#8217;t know when Cheryl&#8217;s birthday is, but I know that Bernard doesn&#8217;t know either.<br \/>\nBernard: At first I didn&#8217;t\u00a0know when Cheryl&#8217;s birthday is, but I know now.<br \/>\nAlbert: Then I also know when Cheryl&#8217;s birthday is.<br \/>\nSo when is Cheryl&#8217;s birthday?&#8221;<\/p><\/blockquote>\n<p>There is an actual, logical answer to this problem\u2014unfortunately it doesn&#8217;t answer why Cheryl doesn&#8217;t just want to tell everyone what her birthday is. A lot of it is built around deriving logical statements, but if you read up on the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Cheryl%27s_Birthday\" target=\"_blank\" rel=\"noopener\">solution<\/a>, you can figure out how this is solved.<\/p>\n<p><em>Thanks a ton<\/em>, Cheryl.<\/p>\n<p>We&#8217;re Areteem. <a href=\"https:\/\/areteem.org\/about\/contact\" target=\"_blank\" rel=\"noopener\">Contact us<\/a> if you&#8217;d like to learn what&#8217;s in store.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>It seems like a lot of folks loved the previous post, so we&rsquo;re going at it again! Here are three<\/p>\n","protected":false},"author":1,"featured_media":1583,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[87],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>3 More of the Weirdest Math Problems\u2014Continued - Areteem Institute Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/areteem.org\/blog\/3-more-of-the-weirdest-math-problems-continued\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"3 More of the Weirdest Math Problems\u2014Continued - Areteem Institute Blog\" \/>\n<meta property=\"og:description\" content=\"It seems like a lot of folks loved the previous post, so we&rsquo;re going at it again! 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