matrix wrote:the more teams that join the less chance each one has of winning...
If you mean the premiership, rather than each week, that is true (all things being equal). That is, one out of 18 is less than one out of 17, which is less than one out of 12.
...if ten people do saturday lotto this week i have more chance of winning it than if 100 do it
But that's not true. The chances of picking the winning combination of Tattslotto numbers on a Saturday (one in 8,145,060) does not change no matter how many people enter, the only thing that may change is that more people pick that winning combination thereby lessening your share. However, you can improve your chances of winning by taking more combinations. If you take all 8,145,060 combinations, you are certain to hold the winning combination. Whether you "win" on your rather large outlay will depend on how many others choose the same combination.
A correct analogy with Lotto type games would be to compare your chances of winning under "Old Lotto" when there were just 40 numbers to choose from (one in 3,838,380), with current Tattslotto where there are 45. Your chances of winning decreased significantly (more than 50%), which meant that the "prize" increased, given that the same amount was invested on the game.