several teams took part inn competition , each of which must paly one game with another team. how many teams took part in competition if they played 45 games in all?

Question

anonymous · Answer

I assume each one must play one game with EACH other team, yes? If so, then the first team must play each of the other teams. The second team must then play each of the other teams except the first (because they already played), the third must play each of the teams except the first two, etc. So for 5 teams the number of games is 4 + 3 + 2 + 1. Can you figure it out now?