If you bet on “red” at roulette, you have chance 18/38 of winning. Suppose you make a sequence of independent bets on “red” at roulette, with the decision that you will stop playing once you’ve won 5 times. What is the chance that after 15 bets you are still playing?

Question

perl · Answer

ok ill try again but

perl · Answer

do you have the answer to check ?

seba_beto · Answer

I have the asw. my problem is in understanding lol

perl · Answer

i just need to know it is right before explaining it

seba_beto · Answer

yeah me too!

seba_beto · Answer

it is

perl · Answer

$$P(x <5)=\sum_{k=0}^{4}\left(\begin{matrix}15 \ k\end{matrix}\right)\left( \frac{ 18 }{ 38 } \right)^k \left(\frac{ 20 }{38 }\right)^{15-k}$$

perl · Answer

makes sense?

seba_beto · Answer

sort of...

seba_beto · Answer

I've got it!!! it's just a binomial proba. thx