1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Probability question

  1. Feb 3, 2008 #1
    Hi all,

    It's rather long time I haven't dealt with maths. Now I have this problem.
    A man can shoot right on the target with the probability of success of p = 30%. The question is how many shots does he need to shoot to be 95% (P) successful.

    My idea is :
    Let n the number of shots needed. Then P = p^n+p^(n-1)*q+p^(n-2)*q^2....+p*q(n-1)
    where q=1-p.
    Am i right and if yes, how can I shorten the result?

    Thanks for any help.
     
  2. jcsd
  3. Feb 3, 2008 #2
    In the expansion p^n + n*p^(n-1) +++q^n, it is the first term that tells us the probability that all of the n shots would be successful. The next term tells us of one failue and n-1 successes. But those terms are not what we are looking for. So I think that's a start on the problem.
     
    Last edited: Feb 3, 2008
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Probability question
  1. Probability Question (Replies: 2)

  2. Probability question (Replies: 4)

  3. Probability Question (Replies: 21)

  4. Probability Question (Replies: 3)

  5. Probability questions (Replies: 1)

Loading...