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Question about probabilities in a game of rock-paper-scissors

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#1 swordfish



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Posted 29 January 2014 - 08:02 PM

hello, i was wondering if any of you can help me figure this out.

I'm playing a game of rock-paper-scissors against a computer. My goal is to win 15 times in a row.
Let's say that the computer picks rock/paper/scissors in a completely random way; it doesn't use a pattern nor does it have AI.


My question is, if I were to play against the computer non-stop until i meet my goal (or i die), which approach would have the best chance of getting 15 wins in a row?

A. Keep playing ROCK all the way.

B. Using a pattern i.e. ROCK -> PAPER -> ROCK -> SCISSORS -> PAPER -> SCISSORS then repeat

C. Randomly choosing between rock/paper/scissors every round.

D. They are all equally bad/good.

E. The above are all crap, use this --> (INSERT BEST APPROACH HERE).

F. Other answer. (please specify)

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#2 phil1882


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Posted 02 March 2014 - 04:06 PM

since random is the optimal strategy, the best way to beat it is to be random yourself.

the chances of winning 15 in a row are roughly (1/3)^15  = .0000006969 %

which means you should do so after roughly 1 million games.

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#3 bonanova



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Posted 01 April 2014 - 04:22 AM

The answer is D.

Since the computer plays randomly, your chance of winning does not depend on the strategy you use.

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