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#1 2009-11-13 04:49:52

rksworld
Member
Registered: 2009-11-13
Posts: 8

probablity

the probablity of getting a head on a single toss of a coin is p.consider that A starts and continues to flip the coin until a tail shows up, at which point B starts flipping. then B similarly continues until A takes over and so on. let P(n,m) be the probablity that A accumulates a total of n heads before B accumulates a total of m heads.
  prove that:-
               P(n,m)= pP(n-1,m)+(1-p)(1-P(m,n))

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#2 2009-11-14 11:00:56

gckc123
Member
Registered: 2009-10-19
Posts: 15

Re: probablity

you can do a first step analysis for this question.
P(A gets n heads before B gets m heads)
= P(A gets n before B gets m | first toss is head)P(first toss is head) + P(A gets n before B gets m | first toss is tail)P(first toss is tail)

Cheers

Last edited by gckc123 (2009-11-14 11:02:00)


Maths is fun!

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#3 2009-11-14 16:22:12

rksworld
Member
Registered: 2009-11-13
Posts: 8

Re: probablity

plz give the details ...
not able to understand
by d way
thanxxxx
but nothin to cheer for me

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#4 2009-11-14 16:28:14

gckc123
Member
Registered: 2009-10-19
Posts: 15

Re: probablity

I used law of total probability and conditioned on the first toss.

Try to think about what the following probabilities are

P(A gets n heads before B gets m heads | first toss is head)
P(first toss is head)

Last edited by gckc123 (2009-11-14 16:54:51)


Maths is fun!

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#5 2009-11-15 08:57:06

rksworld
Member
Registered: 2009-11-13
Posts: 8

Re: probablity

thanx dude........
at last i reached the solution

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