Math word problem
posted by Marko on .
At. The first meeting of a chess club the 9 members decide to have a tournament in which each player plays a game against every other player. How many games will there be??
Can you help me figure this out ?

Each of the 9 players would play against 8 others, that would give us 9x8 or 72
BUT, wouldn't that include such games as
A vs B and B vs A, which is the same game.
So we have to divide by 2 to get all those duplications taken out
number of games = 72/2 = 36
In mathematical symbols that would be
C(9,2) = 9!/(2!7!) = 36 
John has five more than twice the number of CDs that Kate has. Together they have 100 CDs

It's always a pleasure to hear from someone with exstpeire.