Unfortunately there is not really a simple answer to this - for a given winning chance the true chances of a horse running a place are largely determined by the chances of all the other horses in the race winning or running a place.

For example if you have a race with 8 runners with a short priced fav, another runner at $3 and everything else at 10/1 or higher then the chances of the $3 shot running a place are very high so you would expect it to only pay a bit over $1.

In another race where the favourite is $3 but the other 7 runners are all under 10/1 then the chances of the favourite running a place are still good but probably not as high as the first example (as more of the other runners have realistic chances of beating it). Therefore you would probably expect this $3 shot to pay more for the place than the first example.

So in short you can expect different place probabilities (and therefore prices) for runners with the same win price (in different races).

There is a formula for working out the expected place chances, given the winning chances of each runner in a race but it is quite complicated. If you are interested let me know and I will put an example up on the tipping website when I have a chance.

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"Computers can do that????" - Homer Simpson