Re: Insoluble marbles-in-urn problem?
- To: mathgroup at smc.vnet.net
- Subject: [mg119985] Re: Insoluble marbles-in-urn problem?
- From: Ray Koopman <koopman at sfu.ca>
- Date: Mon, 4 Jul 2011 06:43:52 -0400 (EDT)
- References: <firstname.lastname@example.org>
On Jul 3, 1:14 am, John Feth <johnf... at gmail.com> wrote: > There is a huge urn full of marbles, each marked with a single digit: > 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. The marked marble quantities are > uniformly distributed between all of the digits and the marbles are > thoroughly mixed. You look away, choose 10 marbles, and put them in > a black velvet bag. > > When you have some time, you look away, open the bag, and remove one > marble. You close the bag, look at the digit on the marble, open a > beer perhaps, and calculate the probability that there is at least > one more marble in the bag with the same digit. P(at least one more marble with the same digit) = 1 - P(no more marbles with the same digit) = 1 - (9/10)^9 = .612579511