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Quick probability question.

  1. Aug 24, 2005 #1
    my brother needs to know this but i'm in exam block right now and can only think of the physics im studying this term. i cant remember how to figure this out anymore i just know i'll have to use nCr and nPr.
    heres the question:
    how do i find the probability of getting tossing 3 heads in a row out of 64 tosses?

    thanks
     
    Last edited: Aug 24, 2005
  2. jcsd
  3. Aug 24, 2005 #2

    EnumaElish

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    Suppose you had one toss only. What is the prob. of a head?

    Suppose two tosses. What is the prob. of 2 heads?

    Suppose 3 tosses. What is the prob. of 3 heads?

    Now, the hard one: in 4 tosses, what is the prob. of one head only? The prob. of 2 heads (regardless of their order)?

    The really difficult ones: with 4 tosses, what is the prob. of 2 heads in a row? 3 heads in a row?
     
    Last edited: Aug 24, 2005
  4. Aug 24, 2005 #3
    1st find the desired sample space ie: how many ways are there to have 3 heads in a row out of 64 tosses? don't rush to nCr and nPr just now, think about the possibilities.
    then find the total number of possibilities and use the definition a probability.
     
  5. Aug 24, 2005 #4

    EnumaElish

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    To find the sample space you might start from just one toss, then 2 tosses, then 3, 4, ... etc. and make a list of all possible outcomes for each case.
     
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