Raffle odds. 10 bought, 400 available. What is 1/x

[NotAllThere]

I'm not an expert but I think its to do with the 1st ticket has a 1/420, the second has a 1/419, the third has a 1/418 etc so overall 10/420 is not quite 1/42

Not so. Basic probability as taught to 14-16 year olds. But it does show that muddled thinking with probability can get confusing.

[Paralytic]

Not so. Basic probability as taught to 14-16 year olds. But it does show that muddled thinking with probability can get confusing.

If you're teaching probability to a bunch 14-16 year olds, what are the odds that at least one of them is on TikTok?

[BrilloPad]

Not so. Basic probability as taught to 14-16 year olds. But it does show that muddled thinking with probability can get confusing.

So well beyond the comprehension of CUK posters then.

[d000hg]

Or has fallen for one of those "£50 a ticket for a £750k house" scams

I saw a cleaning lady raffling tickets for a free cleaning appointment. Would work out her getting about £100/hr.
Loads of people round here raffling a PS5, etc. Basically making money off ill-educated, poor people.

[Paralytic]

I saw a cleaning lady raffling tickets for a free cleaning appointment. Would work out her getting about £100/hr.
Loads of people round here raffling a PS5, etc. Basically making money off ill-educated, poor people.

Did you win anything?

[NotAllThere]

I saw a cleaning lady raffling tickets for a free cleaning appointment. Would work out her getting about £100/hr.
Loads of people round here raffling a PS5, etc. Basically making money off ill-educated, poor people.

Basic MO of the National Lottery then. A tax on the innumerate.

[northernladuk]

Did you win anything?

Well he's now got to clean someone blokes house in lacy panties while the owner jacks off in rubber gloves. But he's made 100 quid so guess he's a winner.

[d000hg]

Basic MO of the National Lottery then. A tax on the innumerate.

Not really. 95% of money spent on Lottery tickets goes back to winners and charities. And your expected return is about 50%, not some chav making 2 grand tax-free for a PS5.

[Lance]

Hmm.. Someone has said that's not the case and come up with some half arsed explaination I don't understand so got myself in knots. Can't find a site explaining this but I expect it's because its so obvious?

if there are multiple prizes it works like this.

Assumption. Once a ticket is drawn it is not put back.

1st prize = 10/400
2nd prize = 10/399 (or 9/399 if you won the 1st)
3rd prize = 10/398 (or 8/398 if won both already)

To find the chances of winning anything, you OR them.
OR is a an addition, so it's 30/1197