<story><title>South Africa&apos;s lottery probed as 5, 6, 7, 8, 9 and 10 drawn</title><url>https://www.bbc.co.uk/news/world-africa-55154525</url></story><parent_chain><item><author>crazygringo</author><text>Does anyone have any idea how many daily &amp;quot;official&amp;quot; lotteries are drawn worldwide?&lt;p&gt;I&amp;#x27;d guess something on the order of 1,000 maybe? (One per country, plus a bunch more for individual states within countries?)&lt;p&gt;I know they vary in numbers of positions and values, but I am kind of curious roughly how often you can expect a sequence of consecutive numbers (increasing or decreasing) to be chosen anywhere worldwide.&lt;p&gt;As an initial guess, if it&amp;#x27;s 5 balls drawn from 50, a thousand times a day, then it&amp;#x27;s something like a ~13% chance to happen &lt;i&gt;somewhere&lt;/i&gt; yearly.&lt;p&gt;So since this is international news, and not the kind of thing that gets reported every year... it doesn&amp;#x27;t seem implausibly unlikely, no? (It&amp;#x27;s not like it&amp;#x27;s a once-in-a-millenia or once-in-earth&amp;#x27;s-lifetime kind of thing.)</text></item></parent_chain><comment><author>mrb</author><text>They draw 6 balls out of 50. There are C(50,6) = 15,890,700 possible draws (C(n,k) = binomial coefficient)&lt;p&gt;45 of the draws are made of 6 consecutive numbers (1-2-3-4-5-6, then 2-3-4-5-6-7, etc, until 45-46-47-48-49-50)&lt;p&gt;A single draw has a 45 out of 15,890,700 chances of being 6 consecutive numbers&lt;p&gt;A single draw has a probability of 1-(45&amp;#x2F;15,890,700) of NOT being 6 consecutive numbers&lt;p&gt;Assuming 1000 draws (lotteries) per day, in a year we expect probability (1-(45&amp;#x2F;15,890,700))^(1000*365) = 36% that none of the lotteries draw 6 consecutive numbers&lt;p&gt;So there is a 64% probability that at least one lottery will draw 6 consecutive numbers in a year. If there are 1000 draws per week (instead of per day) the probability is still 17% that this will happen in a year.&lt;p&gt;So this South African draw is kinda expected.</text></comment>
<story><title>South Africa&apos;s lottery probed as 5, 6, 7, 8, 9 and 10 drawn</title><url>https://www.bbc.co.uk/news/world-africa-55154525</url></story><parent_chain><item><author>crazygringo</author><text>Does anyone have any idea how many daily &amp;quot;official&amp;quot; lotteries are drawn worldwide?&lt;p&gt;I&amp;#x27;d guess something on the order of 1,000 maybe? (One per country, plus a bunch more for individual states within countries?)&lt;p&gt;I know they vary in numbers of positions and values, but I am kind of curious roughly how often you can expect a sequence of consecutive numbers (increasing or decreasing) to be chosen anywhere worldwide.&lt;p&gt;As an initial guess, if it&amp;#x27;s 5 balls drawn from 50, a thousand times a day, then it&amp;#x27;s something like a ~13% chance to happen &lt;i&gt;somewhere&lt;/i&gt; yearly.&lt;p&gt;So since this is international news, and not the kind of thing that gets reported every year... it doesn&amp;#x27;t seem implausibly unlikely, no? (It&amp;#x27;s not like it&amp;#x27;s a once-in-a-millenia or once-in-earth&amp;#x27;s-lifetime kind of thing.)</text></item></parent_chain><comment><author>tyingq</author><text>&lt;i&gt;&amp;quot;Does anyone have any idea how many daily &amp;quot;official&amp;quot; lotteries are drawn worldwide?&amp;quot;&lt;/i&gt;&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.gamblingsites.org&amp;#x2F;blog&amp;#x2F;how-many-different-lotteries-are-in-the-world&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.gamblingsites.org&amp;#x2F;blog&amp;#x2F;how-many-different-lotter...&lt;/a&gt;&lt;p&gt;Looks like a reasonable analysis. Their total is 180.</text></comment>