Doubling down, also called a martingale strategy. This was awesome while it lasted. I used this while playing with dogecoin, the trouble started when I automated it using a script.

Trouble is, even when the chance of losing is 0.25%, you'll lost once every 400 games.

And at one point, the loss will be greater than all the money you had.. and there's no coming back from that.

He said 75% chance, so odds are against you.

Actually, he meant a 75% chance of winning..

Given the chance of winning a round is p=0.5, the chance of losing is q = 1 - p = 0.5

If you've lost the first round, the odds of you twice in a row are q = 0.5^(2 rounds) = 0.25

Which means the odds of you winning are p = 1 - q = 1 - 0.25 = 0.75.

Right, but the expected value of the gamble is negative.

Expected value is 0, right? .75 * 10000 - .25 * 30000

This won't work: https://blog.tafkas.net/2009/06/09/a-not-so-safe-betting-str...