math
posted by Andrew .
In a sports league of n teams in which each team plays every other team twice, the total number N
of games to be played is given by N = n2  n. What is the total number of games to be played in a
football league having 17 teams?

n = 17
N= (17*2)  17 
Thanks Cheryl :)

The answer given by Cheryl is incorrect.
The number of 2 element subsets (which the above deals with) is C(n,2)
= n!/ ((n2)!2! )
= n( n1)/2
so for a double roundrobin, the number of games
= 2* (n(n1)/2
= n(n1)
= n^2  n
so for 17 teams, n=17
N = 17^2  17 = 272
looks like Cheryl read your formula as 2n  n
which would have been simply n, thus her answer of 17