Evens And Odds

A SKIT: The skit has two parts, a "W.C. Fields type swindler" and a "College Kid". The scene is a gate at Chicago O'Hare Airport.

Swindler: Hey college kid, what are you doing?

College Kid: I'm flying back from Boston. I took one of those "earn up to $50 and hour" jobs, but it didn't work out. I'm waiting for a flight to Denver which is two hours overdue.

Swindler: Hey, I'm waiting for the same flight. Want to do something to pass the time?

College Kid: Sure, but what?

Swindler: Want to play a game?

College Kid: What sort of game?

Swindler: How about even-and-odd?

College Kid: What's that?

Swindler: I'll be odd, because I'm so odd. And you be even.

College Kid: I like being even.

Swindler: That's just the way I like it. Now here's how we play. We both count "one-two-three". At "three", we each hold up one or two fingers. If the sum of the fingers is even, you win and I pay you the sum. However if the sum of the fingers is odd, I win and you give me the sum.

College Kid: So it's a gambling game.

Swindler: Yep, the most interesting games are.

College Kid: I like gambling. I been to those new casinos in Central City and Blackhawk. I do real well, though I always lose money in the end.

Swindler: Great!

College Kid: Is this game fair?

Swindler: Every game is fair to someone. You can win either $2 or $4. I can only win $3. So you have two way of winning to my one.

College Kid: So I'll make money! I like this game.

Swindler: So you want a play?

College Kid: You bet!

They now proceed to play.


Within your group of four, divide up into two pairs to play this game. You will be playing with your partner for ~ 5 minutes, then you will switch and play with the other person in your group for ~ 5 more minutes.

These are the questions you will need to answer when you come back from your pairs and join your group of four:

Who seems to win most of the time?



Why do you think this is so?




What is the probability that the even person will win a round?




What is the probability that the odd person will win a round?




What is the optimal strategy for each player?



The Discrete Mathematics Project