Joe wrote:Do you remember how they calculated the number of lines i.e. 8 from 11 = 165 lines
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I note that they refer to PERMS, which I think might mean permutations. But I think that they would really be combinations, becuase, if I remember from school mathematics, in a permutation the order matters whereas in a combination it does not.
So, for example, suppose a woman has one red ribbon, one yellow ribbon and one blue ribbon.
If she is to choose first a ribbon to tie in her hair, then one to tie on the handle of her handbag, then there are six possibilities. Three possibilities for the first choice, then two possibilities for the second choice, so six possible results.
However, if she is to choose first a ribbon to tie in her hair, then a second ribbon to tie in her hair, then there are six possibilities of the choices, yet only three possible results as the two chosen ribbons are treated equally, so the order of choosing is unimportant.
But back to the football pools "PERM".
How do we get 165 from 8 out of 11?
Not knowing from the football pools application but from the maths classes, it is something like, eleven choices times ten choices times nine choices times ... four choices, divided by one times two times three times ... eight.
So lots of them cancel out, leaving eleven times ten times nine, divided by one times two times three.
So what is that?
Changing ten divided by two to five, and changing nine divided by three to three leaves eleven times five times three.
So eleven times fifteen.
Thirten squared is 169.
Thirteen minus eleven is two.
Two squared is 4.
169 - 4 = 165
How about that! Yay!
