Eli5: Why can’t you just double your losses every time you gamble on a thing with roughly 50% chance to make a profit

Question

This is probably really stupid but why cant I bet 100 on a close sports game game for example and if I lose bet 200 on the next one, it’s 50/50 so eventually I’ll win and make a profit

In: 4566

Answer 1

This is known as the [Martingale system. ](https://en.m.wikipedia.org/wiki/Martingale_(betting_system)) It is prevented in a couple of ways. You would only end up winning as much as your first bet. You will eventually run out of money on a bad streak. And before that, you will run into the maximum bet.

It is often used in roulette for betting red or black, which is almost 50:50, but not quite because of 0 and 00. If $25 is the minimum and $500 is the maximum bet then you only need to lose 5 times in a row to be over the max, 25-50-100-200-400