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HP Forum Archive 18

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It's Derby Day!
Message #1 Posted by Don Shepherd on 3 May 2008, 10:41 a.m.

In honor of the Kentucky Derby, and since it is held in my home town (Louisville, Kentucky, USA), here is a HP-17bII+ solver equation to calculate the payoff price of a $2 ticket. You can use this equation to make sure that the racetrack is not ripping you off.

First of all, here is how a pari-mutual payoff amount is calculated. There are three pools: win, place, and show. The payoff amount of each pool is calculated separately. The total amount wagered in a pool is the gross pool. From this, a percentage, called the commission (this is the racetrack's profit), is subtracted, giving the net pool. The net pool is payed out to the winners. From the net pool, you subtract the amounts bet on "finishers". In the win pool, there is only one finisher; in the place pool, there are two; and in the show pool, there are three. This amount is divided by the number of betting interests (1, 2, or 3) resulting in the share amount. The payoff amount is then calculated as the (share + amount bet on this horse) / number of $2 tickets. This amount is then rounded down to the nearest dime.

Here is the 17bII+ solver formula. You supply:

comm - commission, like .15 for 15% (the track will tell you this percentage if you bother them enough) pool - 1, 2, or 3 for win, place, and show this - amount bet on this horse fin - amount bet on other finishers nonfin - amount bet on non-finishers

The formula then calculates the $2 payoff amount.

Re: It's Derby Day!
Message #2 Posted by Bill (Smithville, NJ) on 3 May 2008, 1:57 p.m.,
in response to message #1 by Don Shepherd

Hi Don,

Having worked over ten years one block from Churchhill Downs, I'm very familar with the excitement that the Derby brings to Louisville. Especially the hot air balloon race, the parade, the great steamboat race and of course the Derby itself.

Now you have given us one more reason to go to the track - we can make use of our HP calculator hobby. Very good on the solver equation.

I think I remember seeing a Horse Handicap module for the HP-41. Has anyone here tried it out at the track? Is the code in machine code or standard user code? Just curious, I only went to the Derby for the Mint Julips - would never think about betting :)

Don Have Fun - it's a great fun week.


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