DyslexicEngineer

You get something close to that either way. What I want to know is if one person has more than one entry what the effect on the odds would be.

Correct, there is no benefit to being drawn first. Once, a winning entry is drawn then the prize and that number is gone from the pool. Additionally, nobody has the same number.

Well, I am treating all prizes as being equal for the sake of simplicity. So all 500 prizes are effectively the same thing. And for the sake of an overall chance of winning I have combined them.

Hi guys, Currently, trying to determine the percentage chance of winning an imaginary giveaway for 500 prizes. It uses a single entry per person. Say there is 10000 entries and a total of 500 can win with each winner being unique (1 per person). So far I figure that since you can only win once the odds would be: 1/10000 + 9999/10000 * 1/9999 + 9999/10000 * 9998/9999 * 1/9998 + 9999/10000 * 9998/9999 * 9997/9998 * 1/9997 + ... etc How would I go about calculating that if one person was to have 1000 entries instead of just one? For example, say one person cheats and gets 1000 tickets in a raffle instead of just one with the same prize pool and total entries.