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Comment by MaximumYComb | Hacker News Reader

Also,instead of buying $10 in a weekly lotto every week, you save your money and wait for it to cross a threshold of value and then buy using the saved money.

50 entries into a $70 million lotto is better than 1 entry, 50 times onto an average lotto of $2 million. The expected payout of vastly bigger.

I've done the math on my local lotteries and I only buy tickets when the EV of the return is greater than the cost of a single ticket. Even then it's only a small amount of tickets. The odds may be in my favour but they're still really small to win.

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> I've done the math on my local lotteries and I only buy tickets when the EV of the return is greater than the cost of a single ticket.

If you want to get really technical, you also need to consider the number of people playing. When the jackpot gets extra high more people tend to play, so the likelihood of having to split a jackpot (which happens all the time) becomes higher. Without doing the math I would guess EV of the return is rarely ever greater than the cost of a single ticket.

I factored that in when I did that calculations. How often are their multiple winners and when there are multiple, how many. A surprising amount of the return comes from the non-jackpot prizes, 58% or something. You'll see crowds lining up to buy tickets and yet no winner for a few weeks.

What the maths actually says is your $10 is more likely to make money if you don't do the lotto at all.

If you want to make money gambling then you need a game where you play against other people (like poker) rather than against the house because the house will always stack the odds in its favour.

> EV of the return is greater than the cost of a single ticket.

Wait, if your math is correct, why don't you bet the house on this? With a large enough purchase you're guaranteed to make more money than you spend.

Because I don't have the $50 million laying around to do it. The EV is only in my favour when I factor in the small prizes PLUS odds of main jackpot / value of main jackpot.

It doesn't take into account splitting the jackpot. Maybe the expected value is positive if you're the sole winner, but not when 3 other people picked the same numbers as you.

The thing is, his maths isn't correct. Once upon a time some lottery jackpots would occasionally exceed the cost of buying every ticket. But then crime rings cottoned on to that and bought thousands of tickets. Now lotteries take that probability into account and cap the highest rollover amount. Some even have schemes where if there isn't a winning ticket the prize jackpot trickles down to the next highest tickets -- which is a great way to sell massively more tickets and keep the jackpot low enough that it doesn't exceed the ticket price.

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