quick math or excel help

[rattlsnak]

Sounds simple enough but I'm too lazy to try to figure this out.

5 teams who each play a total of 20 games a season. They will play each other on a rotating schedule so how many games total will there need to be scheduled so that all 5 teams will play 20 games as they rotate through each other?

5 x 20 = 100, but that is obviously too many with the overlap.

[lendaddy]

Originally Posted by NotaBRG

I get 100. It takes 20 games for each team to play each other once. Do that 5 times for the full rotation.

Yes, but in the instance where team 2 plays team 3 you get repetition by also listing team 3 playing team 2. He wants to know how many unique games there are, I assume to schedule refs, courts, etc...

[SilberUrS6]

In addition, teams don't play themselves.

For some reason, I'm getting 80. I might have to examine why my number came out like that.

[ZOA NOM]

In order for all 5 teams to play each other once, it will require 10 games:

1 vs 2
1 vs 3
1 vs 4
1 vs 5
2 vs 3
2 vs 4
2 vs 5
3 vs 4
3 vs 5
4 vs 5

Do this twice for twenty games, each team gets a home game and an away game.

edit: dang! three minutes late!

[lendaddy]

I get 50 games.

Each team plays 4 games per rotation. Each rotation consists of 10 unique combinations. To get to 20 games per team total is 5 rotations = 5 x 10.

[mreid]

It says EACH play 20 games, so the answer is 50.

[SilberUrS6]

Originally Posted by mreid

It says EACH play 20 games, so the answer is 50.

Yup. I see where I made my mistake.

[rattlsnak]

So as a formula, I could use:

# of teams x 20 = X/2 ?

(5 x 20 = 100/2 = 50)

[ZOA NOM]

Originally Posted by SilberUrS6

Yup. I see where I made my mistake.

ditto. der.