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Find the probablility of obtaining the 13th out of 20 possible coupons given that you've already obtained the 12th

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Dear Jimmy, your question is not suitable for the scope of this website; please consult the FAQ. You may want to consider posting to math.stackexchange.com instead. – Willie Wong Dec 19 2010 at 0:49
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Your question is not well posed and is also not really suited to a site such as MO. Please read mathoverflow.net/faq#whatnot – Yemon Choi Dec 19 2010 at 0:49

closed as too localized by Gjergji Zaimi, Igor Pak, Willie Wong, Yemon Choi, Tony Huynh Dec 19 2010 at 0:55

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