Is it true that if you play the lotto with the last drawing’s winning numbers, your odds aren’t actually any worse? If so how?

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So a co-worker was talking about someone’s stupid plan to always play the previous winning lotto numbers. I chimed in that I was pretty sure that didn’t actually hurt their odds. They thought I was crazy, pointing out that probably no lottery ever rolled the same five-six winning numbers twice in a row.

I seem to remember that I am correct, any sequence of numbers has the same odds. But I was totally unable to articulate how that could be. Can someone help me out? It does really seem like the person using this method would be at a serious disadvantage.

Edit: I get it, and I’m not gonna think about balls anymore today.

In: Mathematics

37 Answers

Anonymous 0 Comments

The odds of an event happening are 1 in (the number of different possible outcomes). To make it simple, use coins.

The odds of you flipping 3 heads in a row are 1 in 8, because the possible outcomes are:

H h h

H h t

H t h

H t t

T h h

T h t

T t h

T t t

And only one of those is H H H.

But if you have already flipped two heads, what are the odds that the next flip will be heads? 1 in 2. Because the possible outcomes are

H h t

And

H h h

And only one of those is h h h.

What came before doesn’t matter, because it’s a part of the outcome that can’t change anymore, so it is part of ALL future outcomes. So it has no effect on the odds of the next outcome.

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