Venerable 10-spot recalls keno’s pioneer days

April 02, 2002 3:20 AM
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The 10 spot is the original Keno ticket. The original pay rate for the 10 spot is thought to have been invented, rather than calculated. The agreed upon (and historic) standard odds were deemed to be acceptable to the house, and attractive enough for gamblers. Here is a more modern rendering of pay outs on the 10 spot:

0 / 10   $0.00
1 / 10   $0.00
2 / 10   $0.00
3 / 10   $0.00
4 / 10   $0.00
5 / 10   $2.00
6 / 10   $20.00
7 / 10   $120.00
8 / 10   $1,000.00
9 / 10   $7,500.00
10 / 10   $20,000.00

The 10 spot was the only ticket you could pick. There were no 8 spots, 6 spots, or 15 spots. But suppose you owned a Keno game, and wanted to offer a 9 spot for your customers? You are good with numbers, but you have only a mechanical calculator and a pencil and paper. How do you calculate acceptable payouts on a 9 spot?

Eureka! A nine spot is a 71 way 10! Think of it as a field of nine plus one of the remaining 71 numbers. I’ll prorate the nine spot ticket as a 71 way 10 played for $0.01408 per way, a one dollar ticket.

Using the pay table above, we see that a catch on the 10 computes thusly:

0/9   20   1/10   51   0/10   $0.00
1/9   19   2/10   52   1/9   $0.00
2/9   18   3/10   53   2/10   $0.00
3/9   17   4/10   54   3/10   $0.00
4/9   16   5/10   55   4/10   $0.45

(Here we learn why the historic 40 cent 9 rate started paying at 4. Because this is how the Keno pioneers did it.)

5/9   15   6/10   56   5/10   $5.80
6/9   14   7/10   57   6/10   $13.45
7/9   13   8/10   58   7/10   $280.00
8/9   12   9/10   59   8/10   $2,100
9/9   11   10/10   60   9/10   $9,500

As you can see, this pro-Âí­rated 9 spot pay rate is kindred in spirit to the historic 40 cent rate. These days, with our computers, we just punch in a few numbers. This has generally resulted in higher top-end pay outs, and lower frequency tickets.

If you have a Keno question that you would like answered, please write to me care of this paper, or contact me on the web via email at kenolil@math.net. Well, that’s it for now. Good luck! I’ll see you in line!