Poison

Poison

A Game

Instructions: Start off with ten counters. Each team will take a turn, taking one or two

counters each time. The team that must take the final counter, also known as the poison

counter, loses.

Devise a winning strategy to which the game can be won every time with any amount of counters.

To come up with a strategy that works every time the amount of counters must be

consistent. The amount of chips that can be taken in one full turn (both teams taking

their counters) is two, three, and four. For the game to be consistent every time the

best strategy would be to take the opposite amount of counters as the other team (if they

take one then you take two). This gives a total amount of three counters taken in a full

turn. If you were to take the same amount of counters as the other team you could end up

with a total of two counters (them taking one and you taking one) and four (them taking

two and you taking two).

Poison

A Game

Instructions: Start off with ten counters. Each team will take a turn, taking one or two

counters each time. The team that must take the final counter, also known as the poison

counter, loses.

Devise a winning strategy to which the game can be won every time with any amount of counters.

To come up with a strategy that works every time the amount of counters must be

consistent. The amount of chips that can be taken in one full turn (both teams taking

their counters) is two, three, and four. For the game to be consistent every time the

best strategy would be to take the opposite amount of counters as the other team (if they

take one then you take two). This gives a total amount of three counters taken in a full

turn. If you were to take the same amount of counters as the other team you could end up

with a total of two counters (them taking one and you taking one) and four (them taking

two and you taking two).

The key number to a winning strategy is three. This is the only consistent number that

can be taken every time a full turn is completed. So the key step is to take the opposite

amount of counters as your opponent. In the above game where you start off the game with

ten counters, ten is not a multiple of three. So there has to be a way to get the

counters to a multiple of three. I learned through trial and error that if you go second

and take the opposite amount of counters that you always win. So now I have a winning

strategy. I tried this with other numbers and it did not work. Then I realized that ten

is equal to one more than a multiple of three (3x3 1). I tried other numbers that are one

more than a multiple of three and it worked. I tried thirteen (3x4 1), sixteen (3x5 1)

and twenty-two (3x7 1) and my hypothesis was correct. For any number that fits the

formula 3x 1 will win if you go second and take the opposite. But this strategy did not

work for any other numbers.

I started to test some ideas about taking the same amount of counters as the opponent but

I couldn’t come with anything consistent. Therefore the path to a winning strategy could

not be accurately tracked. I also tried going first and taking one on a couple of

different numbers but I would sometimes win and lose. So I took one of the numbers that I

won with while going first and taking the opposite and tried to test another hypothesis on

it.