00:01
Found this problem you're doing with the game with.
00:01
And she has a probability of winning this game of 0 .1.
00:08
Now, it costs her $10 to play, and she is going to play until she either wins or loses her $30.
00:17
And so we want to find the probability that she will win before she loses her $30.
00:22
Now, rather than trying to do this with a distribution, let's just actually write out all of her possibilities here.
00:28
So she could win on the first one.
00:33
There's a 0 .1 chance that that happens.
00:37
Or she could lose on the first one and then win on the second one.
00:45
And so this would be 0 .9, that's the probability of losing, times 0 .1.
00:53
0 .9 times 0 .1, and that's 0 .09.
00:59
Now she could lose on the first two and then win on the third one...