New Posts For Thread: Maths problemhttps://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problemA bag has 2 red balls and 2 black balls. If 2 balls are picked at random the chances are 66.7% that the balls are different colours. My 10yo son was convinced it was 50/50 so I challenged him to a free bet, takind two red and two silver baubles off1. did your maths teacher never tell you to spend an insanely excessive amount of time reading the question before you picked up your pen?2. i'm going to lay you 10/1 about two blue balls coming out, because i think you're special. how much would youhttps://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428810#4194288101. did your maths teacher never tell you to spend an insanely excessive amount of time reading the question before you picked up your pen?2. i'm going to lay you 10/1 about two blue balls coming out, because i think you're special. how much would youThu, 17 Dec 2009 13:16:59 -0600the chances of two reds being pulled out is ....16.66.....5/1thge cnances of two blues being pulled out....16.66......5/1the chances of two odds balls being poulled out is.......66.66....1/2the chances of any matched coloured balls being pulled out ihttps://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428654#419428654the chances of two reds being pulled out is ....16.66.....5/1thge cnances of two blues being pulled out....16.66......5/1the chances of two odds balls being poulled out is.......66.66....1/2the chances of any matched coloured balls being pulled out iThu, 17 Dec 2009 03:39:35 -0600same solution basicallywhen W = 2B you can rewrite the denominator as difference of two squares, then simplify to get:R_B = 1 / ( 1 + ( q / p ) ^ B )q/p = 1/2 and B = 5 gives:R_5 = 1 / (1 + (1/2)^5) = 32/33 = 0.03030303...https://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428602#419428602same solution basicallywhen W = 2B you can rewrite the denominator as difference of two squares, then simplify to get:R_B = 1 / ( 1 + ( q / p ) ^ B )q/p = 1/2 and B = 5 gives:R_5 = 1 / (1 + (1/2)^5) = 32/33 = 0.03030303...Wed, 16 Dec 2009 10:31:14 -0600I'm not familiar with any high falutin' maths stuff, so apologies for the kitchen sink approach!Contrarian, I have the equations as:(where P(91) = prob of winning from 9-1 ahead)P(91)=2/3 + 1/3 P(82)P(82)=2/3 P(91)+1/3 P(73) ...P(28)=2/3 P(37) + 1/3https://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428598#419428598I'm not familiar with any high falutin' maths stuff, so apologies for the kitchen sink approach!Contrarian, I have the equations as:(where P(91) = prob of winning from 9-1 ahead)P(91)=2/3 + 1/3 P(82)P(82)=2/3 P(91)+1/3 P(73) ...P(28)=2/3 P(37) + 1/3Wed, 16 Dec 2009 04:18:13 -0600Apologies to Eldrick if this is just a long-winded version of his method, but you could do this:Get a series of 9 equations relating the probabilities of winning from the various scores. Eg:P(win from 9-1) = 1/3 + (2/3 * P(win from 8-2)P(win from 8-2https://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428594#419428594Apologies to Eldrick if this is just a long-winded version of his method, but you could do this:Get a series of 9 equations relating the probabilities of winning from the various scores. Eg:P(win from 9-1) = 1/3 + (2/3 * P(win from 8-2)P(win from 8-2Tue, 15 Dec 2009 16:01:58 -0600I just played with two jacks and two queens from a deck of cards. 5 points each at start same - different5-54-63-72-83-74-63-72-81-92-81-90-10https://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428590#419428590I just played with two jacks and two queens from a deck of cards. 5 points each at start same - different5-54-63-72-83-74-63-72-81-92-81-90-10Tue, 15 Dec 2009 16:00:21 -0600I ~concur with Mr Bushy0.030303030303030303using a spreadsheet solutionhttps://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428586#419428586I ~concur with Mr Bushy0.030303030303030303using a spreadsheet solutionTue, 15 Dec 2009 15:52:04 -0600Write total bank as B, set constant stake at 1, bet pays even money so at each step bank moves up 1 with prob p, down 1 with prob (1-p)=qSay you stop after your bank reaches some amount WNow let R_B = Pr(Funds reach W before they reach 0, given currehttps://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428582#419428582Write total bank as B, set constant stake at 1, bet pays even money so at each step bank moves up 1 with prob p, down 1 with prob (1-p)=qSay you stop after your bank reaches some amount WNow let R_B = Pr(Funds reach W before they reach 0, given curreTue, 15 Dec 2009 15:33:50 -0600bushy you sound like mr logic out of the vizhttps://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428578#419428578bushy you sound like mr logic out of the vizTue, 15 Dec 2009 13:12:36 -0600cheers bushy and others.https://community.betfair.com/general_betting/go/thread/view/94082/23481790/maths-problem?post_id=419428574#419428574cheers bushy and others.Tue, 15 Dec 2009 13:10:40 -0600