Odds query

punchestown

Folks,

Looking for some help with working out the odds. Take two horses from the field in a race and put them up in a match bet. Now in a 100% market in the win betting, Horse A is 8/1 and Horse B is 20/1. In the match bet you are betting one to finish ahead of the other. Say the win odds is a true reflection of their ability and there are no differentials i.e. horse a has the better chance of finishing in a better placing in the race as horse a is of the greater ability as per his price. How do i work out the respective odds for each of the two (betting to 100%) in a 2 horse race? Is Horse A 2/5 and Horse B 5/2 and is there a simple way to work it out via calculator?

Thanks in advance

k101

The prices in a match bet depend on a lot more than the prices of the 2 horses in the win book. You could have 4 different races with an 8/1 shot and a 20/1 in each and the prices for the match between the horses in each race could be different by a good bit..

punchestown

That is why i was asking where there are no other contingencies. Its purely an odds/mathematical question nothing to with form etc

Cos88

Ok well assuming 100% book and correct prices, if Horse A is 8/1 it will win 1 in 9 races. If Horse B is 20/1 it will win 1 in 21 races. To get these to relate: Over 63 races A should win 7 times and B should win 3 times.

Does this mean A beats B 7 times out of 10 though? I'm not sure it does. If it does and it is that easy you have odds of 3/10 and 10/3 for the match bet.

Do the same thing with a 2/1 shot (C) and a 4/1 shot (D) and you get.....C winning 1 in 3 with D winning 1 in 5. C wins 5 in 15. D wins 3 in 15. C beats D 5 times out of 8? Odds of 5/8 and 8/5.

For an 8/1 shot and a 20/1 shot, in a match bet you get odds of 1.3 v 3.33. For a 2/1 shot and a 4/1 shot, in a match bet you get odds of 1.63 v 2.6.

It looks reasonable enough but you have to assume that their win ratio = the ratio that they finish ahead of each other.

Edit: That's probably all wrong..........! My head hurts.

Healio

(100% line) 2/5 and 5/2 look spot on.

(bookie line) 1/3 and 2/1.

Mellor

Cos88 wrote: »

Ok well assuming 100% book and correct prices, if Horse A is 8/1 it will win 1 in 9 races. If Horse B is 20/1 it will win 1 in 21 races. To get these to relate: Over 63 races A should win 7 times and B should win 3 times.

Does this mean A beats B 7 times out of 10 though? I'm not sure it does. If it does and it is that easy you have odds of 3/10 and 10/3 for the match bet.

Do the same thing with a 2/1 shot (C) and a 4/1 shot (D) and you get.....C winning 1 in 3 with D winning 1 in 5. C wins 5 in 15. D wins 3 in 15. C beats D 5 times out of 8? Odds of 5/8 and 8/5.

For an 8/1 shot and a 20/1 shot, in a match bet you get odds of 1.3 v 3.33. For a 2/1 shot and a 4/1 shot, in a match bet you get odds of 1.63 v 2.6.

It looks reasonable enough but you have to assume that their win ratio = the ratio that they finish ahead of each other.

Edit: That's probably all wrong..........! My head hurts.

I don't think thats right, in fact i'm pretty sure its not.

Does this mean A beats B 7 times out of 10 though? I'm not sure it does. If it does and it is that easy you have odds of 3/10 and 10/3 for the match bet.

Why did you pick the 3 and not the 7, why 3/10 and not 7/10 (with the other 10/7). This is the error.

Odds of 20/1 and 8/1, winrate of 1 in 21 and 9 respectily.
win ratio of 21:9, or 7/3
This is your odds, 7/3 and 3/7

Mellor

Healio wrote: »

(100% line) 2/5 and 5/2 look spot on.

(bookie line) 1/3 and 2/1.

I'm guessing you went with a ratio of 20:8, getting 5:2

You should use the 1 in x number,
try it with very low numbers and it makes sense, say evens and 3/1, the horse at evens should win twice at often as the horse at 3/1
so a price of 3/1 and 1/3 isn't fair,
the 1 in 2 and 1 in 4 values give odds of 4/2 and 2/4 or 2/1 amd 1/2

Cos88

Mellor is obv right. If you get a ratio that A wins 70% and B wins 30% the odds should be 3/7 and 7/3. I was wrong because I used the 10 instead of 7. Healio was wrong because a 20/1 and 8/1 shot don't have a ratio of 20:8 but 21:9.

So for a 2/1 shot and 4/1 shot you get odds of 3/5 and 5/3. For a 5/1 shot and a 6/1 shot you get odds of 6/7 and 7/6. Dont even need a calculator to work it out! Thanks Mellor.

Healio

How many time have you seen 3/7 and 7/3 in a bookies?

3/7 = 0.42 (2/5 = 0.4)

7/3 = 2.33 (5/2 = 2.5)