Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Probability anyone?

  1. Dec 8, 2004 #1
    Can anyone tell me how I would solve this question:

    A bag contains 3 white balls and 2 black balls. The first draw produced a white ball. The first ball is not replaced. What is the probability that the second draw will produce another white ball?
     
  2. jcsd
  3. Dec 8, 2004 #2

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    You mean it's not put in the bag again.Okay...
    Hint:What was the probability of pulling a white ball in the beginning??What is the formula of probabilities??How would you go abot now...??

    Please,show me how you think.The purpose of this forum is to guide U solve the problem,not me..!!
     
  4. Dec 8, 2004 #3
    Ok well i see the probability of drawing a white ball at the beginning as being 2/5
     
  5. Dec 8, 2004 #4
    Might want to recheck your work.
     
  6. Dec 8, 2004 #5

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    How did u figure that out...??It's important to show your judgement,as well,since apparently it is to blame for erroneous results...
    Again...??What' the initial probability and why.......??????????
     
  7. Dec 8, 2004 #6

    HallsofIvy

    User Avatar
    Science Advisor

    No, at the beginning the bag contained 5 balls, 3 of which were white.
    The probability of drawing a white ball, at the beginning was ?/5.

    However, your original question is different. After drawing a white ball out, the bag has 4 balls left, 2 of which are white. What is the probability of drawing a white ball now?
     
  8. Dec 8, 2004 #7
    When simplified the probability now is 1/2.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook