Ok. So far I'm with you.
What I'm trying to do is build a program that can produce the smallest set of tickets.
"So, the more tickets we buy, the more such 3-ball combinations we cover. What we need, is a set of tickets that covers all 13983816 possible draws."
Yes, that's the current 163 tickets.
But what is the minimum number needed? There must be a mathematical proof.
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by: Infinity08Posted on 2009-08-04 at 07:11:14ID: 25013991
>> What I don't understand is why 163 tickets is required to guarantee a 3 ball win.
That's just the current minimum that someone found. There might be a solution with less than 163 tickets.
>> Any SIMPLE explanations?
I'll try to keep it simple, but that also means that it will only cover the basics :
There are (49! / (6! * 43!)) = 13983816 possible ways of drawing 6 balls out of 49.
Each of these has (6! / (3! * 3!)) = 20 different 3-ball combinations.
There are (49! / (3! * 46!)) = 18424 possible 3-ball combinations.
Over all possible ways of drawing 6 balls out of 49, each of the 18424 3-ball combinations will occur ((13983816 * 20) / 18424) = 15180 times.
So, with one 3-ball combination, we cover 15180 out of 13983816 of all possible draws.
We're looking for which tickets we need, to have at least 1 match with such a 3-ball combination.
Remember that each ticket covers 20 different 3-ball combinations.
So, the more tickets we buy, the more such 3-ball combinations we cover. What we need, is a set of tickets that covers all 13983816 possible draws.
So, suppose we buy a ticket (1, 2, 3, 4, 5, 6). The 3-ball combinations we cover are :
(1, 2, 3), (1, 2, 4), (1, 2, 5), (1, 2, 6), (1, 3, 4), (1, 3, 5), (1, 3, 6), (1, 4, 5), (1, 4, 6), (1, 5, 6),
(2, 3, 4), (2, 3, 5), (2, 3, 6), (2, 4, 5), (2, 4, 6), (2, 5, 6), (3, 4, 5), (3, 4, 6), (3, 5, 6), (4, 5, 6)
This single ticket covers all possible draws that have at least one of these 20 3-ball combinations.
The idea is to find a combination of tickets that covers all 13983816 possible draws in this way.