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

Need Help for solving probability problem

  1. Jul 11, 2009 #1
    I am new to Probability and i was unable to understand how to find i found this problem in schaum discrete mathematics book.
    p(a)=0.6 p(b)=0.3 p(a and b)=0.2 how to find
    (a). A but not B occurs
    (b).B but not A occurs
    (c).A or B occurs
    (d).neither A nor B occurs
    any help...
     
  2. jcsd
  3. Jul 11, 2009 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi srinivas2828! Welcome to PF! :wink:

    Let's start with (a).

    You have the probabilities of A B and AB,

    and you want the probability of AB' (where ' means "not") …

    so how can you combine A B and AB to give you AB' ? :smile:

    (what must you subtract from A to give AB' ?)
     
  4. Jul 11, 2009 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Another way to do this: Draw two overlapping circles, representing "A" and "B". The overlap is "A and B". Since P(A)= 0.6 (Please don't write "a" and "A" to mean the same thing!) the "size" of set A is .6. Since P(A and B)= 0.2 the "size" of the overlap is 0.2. What does that leave for the part of A and that is NOT in B (A and not B)?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Need Help for solving probability problem
Loading...