- #1

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Tom, Dick and Harry play .the following game. They toss a fair coin in

turns. First Tom tosses, then Harry, then Dick, then Tom again and so on

until one of them gets a Head and so becomes the winner. What is the

probability that Tom wins?

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- Thread starter danniim
- Start date

- #1

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Tom, Dick and Harry play .the following game. They toss a fair coin in

turns. First Tom tosses, then Harry, then Dick, then Tom again and so on

until one of them gets a Head and so becomes the winner. What is the

probability that Tom wins?

- #2

tiny-tim

Science Advisor

Homework Helper

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Hi danniim! Welcome to PF!

Show us what you've tried, and where you're stuck, and then we'll know how to help!

- #3

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Okay well my main problem is that I don't know what formula to use.

I thought you would use p(q)^x-1 where p is the probability of success(0.5) and q is the probability of failing (0.5), x is supposed to be the number of trials ie the number of times the coin is tossed but this is not given. This leaves me with the following:

0.5(0.5)^x-1 = ?..... two unknowns.

So clearly I am not understanding something in the question.

- #4

tiny-tim

Science Advisor

Homework Helper

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I thought you would use p(q)^x-1 where p is the probability of success(0.5) and q is the probability of failing (0.5), x is supposed to be the number of trials ie the number of times the coin is tossed …

Hi danniim!

(

Yes, you use pq

Now add up for all the n's that make Tom the winner.

- #5

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Thanks! :)

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