Results 1 to 2 of 2

Math Help - Probability

  1. #1
    Member
    Joined
    Aug 2008
    Posts
    218

    Probability

    Please show any working out. Any help will be apprciated.
    __________________________________________________ __________________________________________________ __
    My tennis coach analyses every game that I play. She has found that I get the first serve in about 70% of the time. When I get the first serve in, I win the point about 80% of the time. If I miss the first serve, the second serve goes in about 90% of the time. When this happens, I win the point about 30% of the time.
    a) Find the probability that I win a point when I am serving
    b) If I win a point while serving, what is the probability that I only
    needed one serve?

    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Joker37 View Post
    Please show any working out. Any help will be apprciated.

    __________________________________________________ __________________________________________________ __
    My tennis coach analyses every game that I play. She has found that I get the first serve in about 70% of the time. When I get the first serve in, I win the point about 80% of the time. If I miss the first serve, the second serve goes in about 90% of the time. When this happens, I win the point about 30% of the time.
    a) Find the probability that I win a point when I am serving
    b) If I win a point while serving, what is the probability that I only
    needed one serve?
    I suggest you draw a tree diagram. Do this and it should be clear where the following have come from:

    a) (0.7)(0.8) + (0.3)(0.9)(0.3) = ....

    b) Pr(First serve in | win the point while serving) = (0.7)(0.8)/[(0.7)(0.8) + (0.3)(0.9)(0.3)] = ....
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 10
    Last Post: January 21st 2011, 12:47 PM
  2. Replies: 3
    Last Post: May 29th 2010, 08:29 AM
  3. fundamental in probability & convergence with probability 1
    Posted in the Advanced Statistics Forum
    Replies: 3
    Last Post: February 23rd 2010, 10:58 AM
  4. Replies: 1
    Last Post: February 18th 2010, 02:54 AM
  5. Replies: 3
    Last Post: December 15th 2009, 07:30 AM

Search Tags


/mathhelpforum @mathhelpforum