how many basketball games are played in a 10- team league if each team plays all other teams twice?

Question

nowhereman · Answer

More than I can count with my fingers.

immanuelv · Answer

:) but what is the answer?

nowhereman · Answer

You should count them. Of course systematically. Start by choosing one team.

watchmath · Answer

Here is the idea. Let say you have 4 teams instead of 10 and they are team A,B,C,D
Team A played: 2,2,2 times with B,C,D 
Team B played: 2,2 times with C, D (the game with A is already counted above)
Team C played : 2 times with D
So in total there were 6+4+2 = 12 games