It is a common misconception that all exactas should pay double the quinella div - the reality is that this is true ON AVERAGE but the marjority of divs will be less than double (but some will be significantly more than double). The reason for this is that if you look at a given quinella combination (say horses 1 & 2) where horse 1 is more likely to win than horse 2 then the Exacta combination 1-2 will pay less than the combination 2-1. The 1-2 combination will also occur more often so you get the impression that Exactas are not paying double the Quinella as you would expect. However when the 2-1 combination does win the payout will be much higher and therefore the average will be maintained.

For example lets say the chances of 1-2 is 12% and 2-1 is 8%. The chance of the quinella 1-2 is therefore 20% (simply being the sum of the chances that the result will be 1-2 or 2-1). Without allowing for TAB take you would expect the divs to be:
Quinella 1-2 $5.00
Exacta 1-2 $8.33
Exacta 2-1 $12.50
Since the 1-2 combination happens 50% more often than the 2-1 combination you might think that the quinella is paying less than double the exacta but if you work it out the long run payout is double the quinella payout

I did a quick query on the Exacta and Quinella payouts for Ascot for the last 12 months and the average divs are as follows:
Quinella $49.32
Exacta $99.95

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