1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Probability of missing items

  1. Jul 22, 2014 #1
    1. The problem statement, all variables and given/known data

    i have problem of finding P(C) , why cant i use the method as in the photo to find P(C) beacuse 1-(all unused stamps are missing)= at least 1 use stamps is missing.

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. Jul 22, 2014 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    C is the event at least one of the used stamps is missing.

    "all unused stamps are missing" would mean there are 14 stamps missing - but the problem statement says only three are missing.

    Did you mean, "all missing stamps are "unused"" - but that is not correct either since at least one of them has to be "used".

    even C is the same as "at most two of the missing stamps are unused"

    You need to comment your working.
  4. Jul 22, 2014 #3
    Ya I mean all the 3 stamps missing are unused.
  5. Jul 22, 2014 #4

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    So if you write: D:=event all three missing stamps are unused, then you want to argue that P(C)=1-P(D), is that what you are saying?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted