JuanitaKelly214
• Posts: 3
Joined: Feb 20, 2020
February 20th, 2020 at 8:24:32 AM permalink
- I have 3000 1on cards (given to me for free) and I want to use them to raise money
- I plan on pre-drawing 20 to 25 bingo numbers (depending on your advice) and selling the cards after the numbers are drawn
- I plan on using them at an event that annually brings approx. 400 people (but I know not everyone will buy a card)

What I need to figure out is;
- How many cards do I need to sell at & what price to make a profit for my non-profit organization
- How many bingo numbers I should pre-draw (20-25?)
- How many cards will get a straight line bingo in how many cards sold, which will indicate how much I should offer as a prize.

I know that there are A LOT of variables in this question, so I know that the answer will not be precise... I just don't want to loose money over-all.

Any info you can give would be greatly appreciated!!!
Wizard
• Posts: 26619
Joined: Oct 14, 2009
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February 20th, 2020 at 9:25:35 AM permalink
Maybe somebody with more time on his hands will help, but I think this is the kind of thing you should be paying to get an answer for.
"For with much wisdom comes much sorrow." -- Ecclesiastes 1:18 (NIV)
ThatDonGuy
• Posts: 6407
Joined: Jun 22, 2011
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February 20th, 2020 at 5:14:56 PM permalink
These numbers seem a bit low, but I ran 20 million games on a single card to see how many balls it would take for that card to get a 5-in-line (with center space free) Bingo:
BallsBingo Prob
101 / 1232.058
111 / 767.165
121 / 502.361
131 / 340.038
141 / 237.02
151 / 170.478
161 / 125.404
171 / 93.93
181 / 71.62
191 / 55.525
201 / 43.718
211 / 34.82
221 / 28.081
231 / 22.87
241 / 18.823
251 / 15.632

Note that each number is for that many balls or fewer

Also remember that this is for just one card
JuanitaKelly214
• Posts: 3
Joined: Feb 20, 2020
February 21st, 2020 at 7:37:42 AM permalink
That's awesome!!!! So if I understand; if I called 21 numbers then 1 in every 35 cards would get a bingo?
ThatDonGuy
• Posts: 6407
Joined: Jun 22, 2011
February 21st, 2020 at 3:44:15 PM permalink
Quote: JuanitaKelly214

That's awesome!!!! So if I understand; if I called 21 numbers then 1 in every 35 cards would get a bingo?

Well, sort of - but you have to remember that it's "1 in 35 cards" if you call 21 numbers even if somebody has a bingo in 20 or fewer.

I assume that, if there is a tie, any prize is split, or there's some sort of drawing for it, so you're only really interested in whether or not anybdy gets a bingo - not necessarily how many.

If there are 100 cards in a game, the probability that nobody gets a bingo in 21 numbers is (1 - 1/34.82)100 = about 1 / 18.43.
JuanitaKelly214