#A math problem with two conflicting answers

17 messages · Page 1 of 1 (latest)

weary saffron
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"if n is defined as the round number and your chances of winning are defined as (1/3)^n what are the chances you will win as n approaches infinity"

I came up this question one day and tried to solve the question but I had conflicting answers between 100% and 50%. Which is correct?

tardy mantleBOT
weary saffron
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to get 100% i thought as you play infinite times, the chances never reach 0 therefore it must be certain

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to get to 50% i used the geometric series "1/3 + 1/9 + 1/27...." which resulted in 1/2

toxic orbit
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probably worth clarifying:
chances to win on round n, or chances of winning at least once after n rounds?

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if it's the former one quickly realizes that the chances of winning rather rapidly approaches 0 as more rounds are played.

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(or maybe there's another interpretation you're using here? in which case it's worth clarifying.)

weary saffron
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I’ll try rephrase the question. The game starts as a 1/3 chance of winning and if you win, the game is over. Otherwise, the game continues with a chance of 1/9 of winning and each round gets thrice as unlikely to win. What are the chances you will win eventually

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Sorry if this is a bit confusing this is the best I could do

toxic orbit
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ah, right.

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so I think it might be easier to ask the complementary question of "what is the probability of you never winning the game as n approaches infinity".

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because then you can subtract what you get from 1 (or 100%), and I believe it may simplify calculations a fair bit.

weary saffron
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ok, thank you!

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.closed

toxic orbit
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it's either .close or .solved.

weary saffron
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alright thanks again!

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.close