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# Rockmond

Member Since 03 May 2012
Offline Last Active Jul 25 2012 04:13 PM

### In Topic: Darts at Morty's

24 July 2012 - 07:49 PM

When Davey and Ian playing together:

Combined probability of hitting a bull's eye will be -

90% + 10% x 80% = 98% (If Davey fails to hit, when going first)
or
80% + 20% x 90% = 98% (If Ian fails to hit, when going first)

Clearly, more than 97% probability by Alex, so Alex definitely made a BAD bet.

Easier to just calculate odds of neither Davey or Ian hitting bullseye: .1 * .2 = .02 or 2%

### In Topic: Darts at Morty's

24 July 2012 - 07:36 PM

Curr3nt did a lot of figuring to come up with the same conclusion I got by multiplying .1 by .2 and comparing it to .03. On 100 throws Alex loses a net 1 time.

### In Topic: Darts at Morty's

23 July 2012 - 04:48 PM

Seems pretty simple. The odds that Davey and Ian both miss is 2% (.2*.1). The odds that Alex will miss is 3%, so he has made a bad bet. Is there something more complicated that I am missing?

### In Topic: Two kids, with a nod to Teanchi and Beanchi

17 July 2012 - 04:54 PM

If Ned said it, probability is 1 that it is GG;
If Red said it, it is either BG, GB, or GG, probability is 1/3 it is GG
If Ted said it, you know the older child is G, probability is 1/2 it is GG
If Zed said it, you know the coin selected child is G. He mentions sex of other child (G) so probability of GG is 1

1/4*1+1/4*1/3+1/4*1/2+1/4*1=17/24 = probability that it is GG.

### In Topic: A Child and a Staircase

21 June 2012 - 05:21 PM

I have a clarification question. If there are 10 steps and a landing at the bottom and the top, the child would have to take 11 steps if taken one at a time, right?