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, flipping a rigged coin problem

  1. Sep 15, 2010 #1
    A coin is loaded so that the probabilities of heads is .52 and the probability of tails is .48.
    If the coin is tossed 3 times what is probabilities that

    a) all heads

    b) 2 tails and a head in that order

    I figured out part a). So i just thought of it with an and statement. ( I want heads and heads and heads) since the previous flip has no bearing on the next flip i can just multiply the quantities,

    so P(all heads) = .52(.52)(.52) = .1406 which is the right answer

    For part b) i am confused some how i have to implement that order is going to matter so I can just multiply them and thats it.
    But still each flip of the coin has no bearing on the other flips so..
    Can someone explain? the answer in the book is .1198
  2. jcsd
  3. Sep 15, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Why do you think you can't just multiply them like in the first case? You have three events occurring in a definite order with a definite probability for each.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook