2006-06-27 09:55:19 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
The probability of winning n times is the ratio of combinations of winners and losers among your tickets to the combinations of tickets drawn:
(winners and losers of your 5 tickets) / (total drawings)
C(5, n) * C(1995, 20 - n) / C(2000, 20), or
[ 5! / (n! * (5 - n)!) ] * [1995! / ((20 - n)! * (1975 + n)!)] / [2000! / (20! * 1980!)]
The probability of winning 0 times is approximately 95.094%, so the probability of winning at least once is about 4.906%.
The probabilty of winning 1 time is approximately 4.812%.
The probabilty of winning 2 times is approximately 0.093%.
The probabilty of winning 3 times is approximately 0.001%.
The probability of winning 4 or 5 times is miniscule.
[Edited below to add comment]
The misconception many people are having is that it's a straight 2000 tickets drawn each time. In a drawing like this, once the first of the 20 winning tickets is picked, there are only 1999 tickets left from which to draw. After the second winner is chosen, the remaining tickets become 1998. You have to use combinations to get the correct probability, here.
2006-06-27 10:10:18 · answer #1 · answered by Anonymous · 0⤊ 0⤋
It is both simple and logic ... think of it like this:
The chances of a given person winning with just 1 ticket is 1/2000 as all of the 2000 tickets have the same chance of being picked.
But... you have 5 tickets i.e. you have 5 times as many chances of winnig as a person having just 1 ticket. => So, your chances are 5 * (1/2000) = 1/400
But the picking is done 20 times so your chances increase again 20 times => your chances are 20*(1/400) = 1/20 = 5%
that is not so good my friend, but remember ... it's not the game it's the way you play it !!!!
P.S. As a de facto thing the probability of a certain event occuring is a number between 0 and 1, 0 meaning never and 1 meaning everytime, so everything above 1 or below 0 is simply not possible
2006-06-27 10:33:21 · answer #2 · answered by calintuns 1 · 0⤊ 0⤋
If the 20 tickets to be drawn are to be drawn from the same 2000 tickets, then the chances are:
5/20 x 2000 = 0.25 x 2000 = 500
In other words, the probability of drawing 20 tickets from a pack of 2000 tickets is 0.25. That is 25% chance!!
2006-06-27 10:23:31 · answer #3 · answered by RealArsenalFan 4 · 0⤊ 0⤋
5/2000 = 1/400
1/400 x 20 = 20/400 = 1/20 =
5%
2006-06-27 10:07:01 · answer #4 · answered by CaliBeachBabe 2 · 0⤊ 0⤋
theres a 4% chance that youl have a ticket drawn from a total of 2000 tickets.
2006-06-27 10:04:00 · answer #5 · answered by Anonymous · 0⤊ 0⤋
No chance. It's scam
2006-06-27 09:58:37 · answer #6 · answered by Igor L 3 · 0⤊ 0⤋