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

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  • Lance
    replied
    Originally posted by northernladuk View Post

    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

    Leave a comment:


  • d000hg
    replied
    Originally posted by NotAllThere View Post
    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.

    Leave a comment:


  • northernladuk
    replied
    Originally posted by Paralytic View Post
    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.

    Leave a comment:


  • NotAllThere
    replied
    Originally posted by d000hg View Post
    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.

    Leave a comment:


  • Paralytic
    replied
    Originally posted by d000hg View Post
    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?

    Leave a comment:


  • d000hg
    replied
    Originally posted by ladymuck View Post
    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.

    Leave a comment:


  • BrilloPad
    replied
    Originally posted by NotAllThere View Post
    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.

    Leave a comment:


  • Paralytic
    replied
    Originally posted by NotAllThere View Post
    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?

    Leave a comment:


  • NotAllThere
    replied
    Originally posted by SimonMac View Post
    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.

    Leave a comment:


  • northernladuk
    replied
    Originally posted by eek View Post
    Card games are all to do with probability.
    Not just probability as there is a cash value as well which brings implied odds and other factors. You are right what you said earlier about those types of odds playing poker and they are a bit ridiculous but if there is value there it makes it worth a bet. If it's 1 in 420 and you have to put £10 in win £300 then that's terrible. If the pot is £20k then you bet every day of the week.

    So it's probability and expected value.

    Leave a comment:


  • eek
    replied
    Originally posted by BrilloPad View Post
    Thats a bit like saying darts players(who are good at subtracting) should be good at maths.
    Card games are all to do with probability.

    Leave a comment:


  • ladymuck
    replied
    Originally posted by SimonMac View Post
    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
    That's for multiple prizes, where a drawn ticket is not returned to the pool.

    Originally posted by BrilloPad View Post
    All 10 have 1/420.
    That's for any one ticket. So assuming only one prize is available.

    Leave a comment:


  • BrilloPad
    replied
    Originally posted by eek View Post
    That's if there are multiple prizes:

    the first ticket is picked from 420,
    the second ticket from 419 and so on.

    With 1 prize the odds are 1 in 420 that a particular ticket wins so with 10 tickets NLUK has a 10 in 420 chance or 1 in 42 chance of winning.

    Worryingly NLUK plays poker so I would expect him to be better at odds than that but I can see he's ended up going number blind.
    Thats a bit like saying darts players(who are good at subtracting) should be good at maths.

    Leave a comment:


  • eek
    replied
    Originally posted by SimonMac View Post
    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
    That's if there are multiple prizes:

    the first ticket is picked from 420,
    the second ticket from 419 and so on.

    With 1 prize the odds are 1 in 420 that a particular ticket wins so with 10 tickets NLUK has a 10 in 420 chance or 1 in 42 chance of winning.

    Worryingly NLUK plays poker so I would expect him to be better at odds than that but I can see he's ended up going number blind.
    Last edited by eek; 15 February 2021, 10:35.

    Leave a comment:


  • BrilloPad
    replied
    Originally posted by SimonMac View Post
    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
    All 10 have 1/420.

    Leave a comment:

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