ok...
im trying to find a way of laying 3 goals exactly on betfair..
anyone got any ideas?
so far iv come up with LAY 2.5 goals & lay 3.5 goals? would anyone be able to help me get a rough idea of what price id be laying the 3 goals exactly if i did this..
very confusing i know..
the way im thinking you can do it on total goals market,but the odds will be the same as 2.5 give or take a point or 2.
cheers
terry.
Will have a go.
AFAIK the only ways to get 3 goals in a game of soccer, are:
03
12
21
30
Now if you were to bet on each of those, you would have what you wanted.
Lay them all, and you have layed 3 goals being scored. 4 bets as opposed to 2, but you are also only paying commission now on 1 market, instead of 2, so you are best off here.
Now here are the odds for Blackburn vs Blackpool, for the scores in order, taking what is available:
140
21
10.5
23
That represents .714%, 4.76%, 9.52%, 4.35% of the market, or a total of 19.35%, or odds of ~$5.169....
Or, if you like, if you layed them:
$7.14
$47.62
$95.24
$43.48
and 3 goals happened, your liability would be 806.52 for a potential gain of 193.48 if it didn't happen. 806.52/193.48 = 4.1685, plus your stake, gives you the same odds of ~5.169 as I stated before.
In regards to laying over 2.5 and laying under 3.5, I will have a look later at how to calculate that but at this stage I don't see why I should bother when the most efficient way to do what you are asking is to use the correct score market as commission only comes out once then.
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Now the other way, as stated in the post before mine, is to go to total goals market.
3+ goals is represented by about 1.68
4+ goals is represented by about 2.60
Problem here is this market has 0 liquidity, but should still go close.
Now, 1.68 is 59.52% market share, 2.60 is around 38.46% market share, a difference of about 21% which is around the chance of 3 goals exactly happening. I said 19.35%, this shows around 21.06%, in a non liquid environment.
Back 3+, lay 4+, job done.
But once again, just go to correct score market, much easier. Dutch all the possible selections. Dutch?
Market share :
= 1/ odds.............
Dutching to exact profit :
= target liability point (eg if you want to bet to return 100, 1000, or whatever)
So:
= 100 * (1/odds)
If you bet to return a figure, no matter how many selections you take in the event, you will always return the same amount of money on a win, and always lose the same on a loss, because you are combining your bets as a total market share.
eg.
You dutch 2 10.00 selections. Each of them has a 10% market share. You bet 10 dollars on each, to represent betting to 100. Your total bet is 20 dollars, because you have effectively bet on 20% of the market, so you will always be betting 20 to win 80, so the chance of your bet happening is 5.00, or 20%.
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joneyyy1981 (14th March 2011)

thanks tem...
yeah the correct score does seem the best way iv found, iv done a couple of games and i seem to be able to lay around 3.88 after %.
i think anyways.
take the man utd game tonight
03  280 @ £3.35p = liability of £737.50
12  32 @ £29.28p = liabilty of £736.96
21  9.6 @ £97.58p = liability of £736.77
30  13.5 @ £69.39 = liabilty of £736.77
total = £200 profit £190 after %.
737.5 divide by 190 = 3.88
is this correct?
i think if i shopped about on some of the prices i could get it lower..
Looks correct to me  I calculated liabilities up to 1 unit difference to your ones, and profit 199.60 before commission.
I used a simple Excel that simulates Correct Score market, which may help you with these calculations; enter your odds and stake in appropriate column ("Lay odds" and "Lay stake") and commission level, and you'll get the figures above; it's here: www.gubbed.me , the one titled "Correct Score market".
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Temujin (15th March 2011)

Well, depending on if you wish to use the commission figure in regards to the odds. Generally, I just use the base odds figure, and know that commission is coming off that.
But you need to add your stake to it.
Your %s add up to 21.32%, or 100/21.32 = 4.69.
737/ 200 = 3.685, which adds up to the 4.69 if you add the stake....
And obviously this figure is lower than yours, because you are laying (explaining to myself, as I was a little confused at first until I remembered LAY... )
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joneyyy1981 (15th March 2011)

thanks guys, tam i get lost when you say add your stake..? makes it 4.69.?? so what odds am i REALLY laying? 3.685 or 4.69? if its 3.6 im good with that, if not im buggered?
Treat everything much the same as you would dutching and convert things to a probability.
So 2/1 fractional odds 3 decimal odds becomes 33.33% (100/3) 4/1 becomes 20% (100/(4+1)) etc
You then just combine those probabilities to get your overall odds
So laying the following decimal odds
8, 8, 9 would become 12.5% + 12.5% + 11.11% = 36.11%
to convert that probability back to odds we just divide by 100 which gives use odds of 2.77 (100/36.11)
Like temujin said in your example the odds would end up at 4.69 (3.69/1 fractional odds)
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joneyyy1981 (15th March 2011)

im still lost by the 4.69 / 3.69 ... which is it 3 or 4?
You're risking 737 units to win 200 units; total payout is 937 units; therefore, you lay at odds of 937 / 200 = 4.69 in decimal format; that is, 3.69/1 in fractional format.
Equivalent back odds are 4.69/3.69 = 1.27; therefore, it's the same as you backed "NO 3 goals" with stake of 737 units; your profit is 27% of your stake.
(Of course, "NO 3 goals" market does not exist; it's just hypothetic to show you profit/loss ratio)
I think it has been well explained, but here is another go.
If you lay at 5.00, for 100, your liability is only 400, because 1.00 of the odds is your stake.
So using your calc, 400/100 gives you odds of 4.00, which is not accurate. Your stake must be included.
Fractional odds, 4/1 represents 4 of their money, 1 of yours. You risk 1 backing, to make 4 off them, the kitty is 5 which is what the decimal odds represents, the kitty.
iv got it into my very small brain i think now...