Cross doubles

[puzzleking123]

if I back 2 horses in 5 races along with 1 horse 6 races how many cross doubles is that please

[R1Geezer]

effectively it's 11 races, that's 110/2=55 doubles minus the 10 impossible ones, so 45, I think, but I'm not 100% on that!

[lesblue]

275......If you want cross-doubles in eleven races, that's fifty-five doubles. However, in five races you have two selections, so the fifty-five has to be muliplied by the five races in which you have two selections. Hope this makes sense.

[R1Geezer]

sorry les not with you, if there was just a straight 11 races with 1 horse in each then the number of doubles is (11x10)/(1x2)=55. so that's the most it can be. There are 10 of those where 2 horses are in the same race so that's 45.

It's not cross doubles in 11 races it's cross doubles in 6 races where 1 has only 1 horse.

[lesblue]

It didnt look right when I put the answer in, Geezer, so I've had another think, and reckon its 130.
OK, here goes..........11 races equals 55 doubles ( I think we're agreed on that). But then, surely, if you have two selections in one race, you are looking at MORE possibilities, not less. I am thinking along the lines of 55 doubles, PLUS ten extra doubles for each second selection ie 60, then 15 extra doubles for the second selections on their own. So 55 plus 60 plus 15 equals 130.
Crikey, I'm even more confused now that I am reading it back ha ha.
I reckon this is one for stokemaverick!!

[R1Geezer]

no by making it 11 we have included the 5 with 2 horses twice. The starting point is 55, that must be reduced by working out how many of those doubles are in fact in the same race.

[lesblue]

I've misunderstood the question, then!! I was looking at eleven races (five with two selections, and six with one selection i.e. 16 selections in all). If it is only six races then you are correct, 45. Now I've got a head ache and I'm off to work. Night night :-)

[mark01]

I make it 115

[R1Geezer]

How mark, I don;t see how it can possibly be more that 55

[mark01]

I've looked at the question again - I'm really not sure what puzzleking is asking.

If the question is a combination bet of 2 horses in 5 races with 1 horse in a further 6 races then there are 115 doubles.

As it now appears it is 2 horses in five races plus 1 horse in the remaining race, making 6 races altogether, then yes it is 45 doubles.

I think I'll make myself a cup of tea!

[R1Geezer]

Yes that's how I see it, is this what you are asking PUzzleking?