Probability question

[jurajcirc]

Hi !

I might be asking a wrong question but let's try.
Outcome A has 65 % probability
Outcome B has 35 % probability

What is the probability that A happens 3 times (not necessarily in a row) before B happens 2 times (not necessarily in a row)?

Thanks a lot!

 

[Steven G]

I think that you misunderstand what this website is all about. Did you read the forum's guidelines? This is a math help forum where we help the student arrive at the correct answer and not a forum where you post a problem and a helper here supplies you with the answer.

Can you please post your attempt at this problem?
Here is a hint. What is the probability that A happens 3 times before B happens twice after 3 trials?
What is the probability that A happens 3 times before B happens twice after exactly 4 trials?
What is the probability that A happens 3 times before B happens twice after exactly 5 trials?
What is the probability that A happens 3 times before B happens twice after exactly 6 trials?
....

 

[Romsek]

Does each trial result in either A or B or are the trials separate, i.e. you have one set of trials that results in A or !A
and another set of parallel trials that results in B or !B.

The two probabilities sum to 1 so probably the first case but it's worth checking.